Not sure if this applies to the DM language but I guess its the most related to it. Anyways since the new BYONDexe forces you to use the byond subscription method I thought it be a good idea to make a system where a developer could choose to sell packages instead of subscriptions. Packages could be special weapons and/or in-game money or something. While a subscription allows a player to get these buffs the package buying could allow multiple packages to be both at the same day.
Basically packages would work this way :
var/package = downloadpackage(hubcode,"packagename")
if(package == 1) usr.contents += /obj/items/
Basically downloadpackage would return either 1 or 0 depending if the person has bought the package or not. Then when the stuff in the if statement is done the developer should be able to terminate the package.
I hope any of this makes sense.
Via subscriptions I guess you can modify your subscriptions and call one - Weapon Package 1 ( single fee ) - and read if they have the sub write to there save file that they have already received the weapon.
or with your own system to handle these, which isn't hard, PayPal IPA that inputs the values into MYSQL which your game reads upon login.