here's an outdated but decent guide on the basic concepts of failstacking:
i'm sure there's better youtube videos out there that are more up to date, if you wanna look around for one. That one is short and sweet and to the point on the basics. just ignore the shit about reblath, don't use that.
and here's the old chart from KR, it shows you how failstacks affect each level of enchant, for green gear. The actual numbers for blue/yellow gear are slightly worse. But this is a good baseline:
keep in mind, 16-20 means PRI through PEN, ie 16=PRI, 17=DUO, 18=TRI, 19=TET, 20=PEN.
There are 2 costs when it comes to enchanting, the cost per attempt (or really, cost per fail stack), and the durability repair cost. Durability is where pearls/"p2w" comes in to play, but i'll explain cost per attempt first, the cost of failstacks:
enchanting is about building up the most cost effective failstacks, for whatever you ultimately want to enchant. The more failstacks you have, the higher your chance of succeeding, so keep in mind, when you are trying to build failstacks, "accidentally" succeeding consumes all your failstacks, and you may be left with an enchanted item you didn't want.
Let's use an example, a +15 green yuria staff is what you ultimately want to enchant.
First you want to get this to PRI (+16), looking at the chart, you have a base 15% success rate, each fail stack adds 1.5% to the chance of success, and your maximum effective fail stacks is 25, which gives you a 52.5% chance of succeeding.
Straight away, 25 FS is too much for PRI, those FS cost more than the attempts, you should be good at 15 Fail stacks (15% base + 15x1.5% = 37.5% chance of success)
So lets start at 0 failstacks. the video suggests reblath or militia gear, ignore this. The cheapest failstacks for 0-5 are generic green jewelry (like yuria belt, hesus necklace, bares ring, etc etc). you can buy these for 30k per on the marketplace. You combine 2 like items (so 60k per attempt), if it fails, you get +1 failstack. if it succeeds you get a PRI whatever, bares ring in this example. The reason you stop at around 5 Failstacks is you are very likely to succeed after that point, wasting all your failstacks. again looking at the chart, PRI green jewelry is the same as a PRI green yuria staff, and 5 FS = 22.5% chance of succeeding. Sure you can keep going for +6 or +7 failstacks on cheap jewelry, but you'll end up eating all your FS more often than not.
Make sure before you start, that you have the other items to build FS on. if you don't have anything to build 6-15 on, then you'll end up wasting these 5 FS you made building up 6-15. The video lists some good items to have already enchanted to certain levels to build failstacks on, such as horse gear and midrange items (like +13 weapons, armor, etc)
So from 6-15 it suggests +7 horse gear, which is decent enough. you can really use anything that has a low chance of success. +9 mount gear, +14 armor and weapons are your sweet ticket items, you can reliably build lots of small FSs using those (up to around +15-18 or so).
Personally I only enchant things that either A: will sell (like Grunil Armor), or B: I can use, or use on an alt. That way, when you accidentally end up +15ing it, you can still recoop some of the costs which went in to making it. You can also go to a blacksmith and extract some of your blackstones back out of it (waste of money on expensive items), or put the gear on a Negative karma alt and die a bunch to mobs/guards, since there is a chance that the gear will delevel due to the PKer penalty (ie from +15 back to +14).
Personally I suggest, if you can afford it, use horse/wagon/boat gear until you have a full set of +10 horse/wagon/boat gear for yourself to use. it's more expensive to repair, but you are building things you are gonna use personally anyway. After that, I suggest using things like Grunil (especially if you make your own armor with workers) because you can always sell that stuff on the marketplace. If you are desperate you can use stuff like Azwell Weapons, since they are like 20k each (for repairing durability), so you don't lose much when extract the stones back out (or if you have a negative karma alt, you can always delevel it back to +14 and keep building FS on it)
to recap:
You spent 60k per FS up to +5 with cheap jewelry: 300k total.
You spent 200k per FS (cost of armor black stone) from +6 to +15 on, say grunil armor. 2mil total
So the cost of your 15 failstack is 2.3mil. At 15 Failstacks, you now have a reasonable chance of upgrading your +15 Yuria staff to PRI. Now you will spend 4mil per attempt (cost of sharp stone and 2x weapon black stones for a concentrated black stone)
If you fail PRI, you will gain 2 FS (17 total), will have to spend another 4mil on another attempt, with a slightly higher chance of success (40.5% at 17 FS)
If you succeed, you will have 0 FS and a PRI Staff.
Once you are at PRI, you will need to look at the chart and see what the chances are for DUO. You can enchant armor/weapons up to DUO with no risk of deleveling the item. After that point, enchanting becomes very annoying/costsly, because if you fail to go to TRI, your item delevels back to PRI and you start over again. TRIs become DUOs going for TET, TETs become TRIs going for PEN. And you can see the chances of succeeding get lower and lower, and the cost for failure gets higher and higher.
You can push your luck and try to build 20-25 failstacks on cheap green items like weapons/armor/mount gear. But as you can see from the above, beyond this point, failstacks start to become very expensive. You are spending 2mil per attempt on armor and 4 mil per attempt on weapons. But to build up 30+ failstacks for things like TRI or higher, thats what you have to do.
Now to other half of enchanting, which is durability repair.
keep in mind, accessories like in the example above, don't lose durability, they just straight up break. You lose both items if the enchant fails. This doesn't matter so much when smashing cheap jewelry together for FSs, since they are like 30k each. But when you are talking about enchanting expensive accessories, you will want failstacks, because you don't want to fail. Losing a DUO witch earring PLUS a normal witch earring when you fail to TRI your witches earring, sets you back more than 120 million. More expensive accessories are even worse. There are CRON stones, but i won't get in to that for now.
For the gear you were enchanting to build failstacks, up to +15, you lose 5 durability for every failure. You have to repair this durability to continue enchanting with the item.
Items you can feed in to other like items to repair 10 durability, or 2 enchant attempts. Even if you are repairing a blue or yellow version of something, you can still use the green base item for repair, so don't let that part fool you. So for say, a +14 Grunil helmet you used to build FS on earlier, once you run out of durability (20 or less), you have to feed it 8 more Grunil Helms (250k each, or 2mil total) to get it's durability back up to 100. 100 durability lets you fail 16 times, ie 16 FS costs you 2mil in durability repair. This is why it's beneficial to build your own armor with workers to failstack on. It's just opportunity cost and some of your time spent lifeskilling, it doesn't actually cost you any money out of pocket.
After +15, each attempt costs you 10 Durability, instead of 5. PRI fails give you 2 fs, DUO gives 3, TRI gives you 4, etc.
Now this is all well in good when talking about green gear. But for more expensive gear, like boss armor/weapons, etc, you can't really use items to repair items. Kzarka Staff costs you 100mil, you wouldn't spend 100mil to repair 10 durability, even if they were so abundant on the marketplace you could buy them at will, which you can't. For this you use Memory fragments instead.
Memory Fragments costs approx 750k each, you can get them from running relics/cartians/pila fe scrolls, and they are used in lieu of a like item, to repair items. They repair:
10 durability for white
5 durability for green
2 Durability for Blue
1 Durability for Yellow
And this is where Pearls come in to play. There is an item called artisan memory, you can buy for 400 loyalty or 50 pearls (40 if you buy in bulk). This item triples the effectiveness of repairs. So if you use it with a Memory Fragment, you can repair 3 durability instead of 1 on a piece of yellow boss gear. So you can see, repairing a Kzarka weapon, spending 40 cents on a artisan memory saves you 1.5mil in the cost of memory fragments.
Where this becomes particular effective, is for blue gear like Livertos or awakening weapons. if you want to repair your awakening weapon, it will cost you 750k per 2 durability using memory fragments (375k per Durability), or 6mil (cost of base blue item) per 10 durability using another awakening weapon to repair (600k per durability). Remember: Artisan Memory triples these.
So you have the following options:
spend 5 Artisan Memories (200 pearls, $2), 5 Memory Fragments (3.75mil) and repair 30 durability, at the rate of 125k per durability
spend 1 Artisan Memory (40 pearls, $0.40), 1 Blue item (6mil), and repair 30 durability, at the rate of 200k per durability
spend 0 RL money, 15 memory fragments (11.25mil), and repair 30 durability, at the rate of 375k per durability
spend 0 RL money, 3 awakened weapons (18mil), and repair 30 durability, at the rate of 600k per durability
So if whipping out your credit card doesn't disgust you entirely, you can spend a few bucks here and there and get real gains when it comes to repair cost. You can even do so on a budget if you use a blue item instead of a bunch of memory fragments, since it's not a huge difference in cost effectiveness RL vs in game currency.
All of that being said, and it's a fucking wall of text. You can just ignore enchanting entirely by straight up buying the gear you want from the AH. TRI is a good level to aim for. It's not so ungodly rare that it'll never get posted (like PEN Ogre rings or what have you) and each piece will only set you back 300-500mil, vs 3-4 Billion.