Rolling 30 day limit. I can't imagine hitting the $320,000 USD a month. Goes to show you that its possible. There are also enterprise limits, which allows you to cash out up to $1,280,000 a month.
Like I said earlier. In my past I couldn't imagine people being so stupid as to buy all these silly avatar things and whatnot, but they do. Trust me, they do. I wish I didn't shun it in the past.
If you all want to take a stab at it from a scripting perspective, you can take a look at the
reference guide for LSL, though SL 2.0 will be using C# which will be nicer. It's basically like unity. You have objects, and you put scripts in objects that make the objects do things. The challenge in SL though are things like no arrays, or no switch... and most of all scripts can only be a certain size and script memory is independent of each other so like if you have a situation where say you want to have a ban list for a security orb, that could take a lot of memory if you have a ton of people on the list. A scripter will do something like have a separate script whos sole purpose in life is to maintain this ban list, and you'd script a "ban add", "ban remove" and "ban check" function. When the core script needs to check if someones banned it (seriously) sends a text message (called a link message) to that script using "ban check" with the persons UUID, and then the ban script sends a link message back to the core script with "found" or "not found" reply. Its sometimes convoluted in complex projects, but you get used to it. Code below is an example of the ban script, including BAN_VERIFY which will return whether they are banned or not...
If you notice all the built in crap starts with ll. Now you know why in my "I need a keyboard thread" the L key was worn to shit. heh.
It also takes a lot of work and effort and time to eventually bring up a good amount of money, but to be honest making something like half a car payment ~$200 a month in SL isn't terribly difficult. Even selling gacha trinkets out of gacha machines should make you that. (google gacha if you want to know what that is).