The place really is a cesspool. There are a ton of twisted, weird, odd, and generally bizarre things that happen there. Dragon cocks, for example, market is already dominated by other players (hahaha).
But again, it can also be a very cool creative playground. It's cool that you can create fucking plants and grass in blender, texture it, and optionally add a script to texture it different types of leaves, different colors, etc...
and sell it. After all there, are sim builders who will build your sim for your needs and those builders will buy things like plants, etc they use to decorate.
And even though you might get involved into the "dark" or "twisted" part of SL as part of your business, you start taking it with a grain of salt. If I develop a complete pregnancy system for SL to allow virtual avatars to poop out babies and shit that's pretty fucking bizarre, but if I'm going to sell 5,000 of them at $5 each, I don't care what anyone thinks, I'll laugh all the way taking my $25k to the bank.
(although,
that marketis mostly cornered but hey if you can do it better...)
Edit: But all joking aside, I should set expectations here. As I said before, it does take a considerable amount of time and effort to really make a lot of money in SL. It's a real business, despite its nature. As I said I have a full blown CPA, Intellectual Property Lawyer who writes things like my terms of service for my products, etc. In SL, you retain ownership of your creations (though you do give LL some rights on your IP such as they can take pictures of it and use it in their marketing material, etc) even going so far as LL will act on DMCA takedowns. Generally, you won't have to go this far (until you are making good money). The average tinker whos going to create a few things in SL, depending on what they are, might get 0 sales or the occasional 1 sale a month or something. Like any other business, you'll have competitors, but there are always ways to be better. If you create a large range of products, and advertise properly, depending on what they are, you can do well. Gacha's (which are like the toy vending machines you used to play at a kid) are a GREAT way to make money by selling little goofy trinkets and stuff, which have a large collectible 3rd party market (you can set permissions on items, and Gacha items are generally no copy, no modify, but transferable meaning you can give it to another avatar, but then its gone from your inventory).