it's a one time fee. you buy it once and you own it for good.
the singleplayer thingamabob is weird. more of a free build than anything since i think you get unlimited material/blocks to do whatever.
in the real deal, you actually have to go out and get the raw material to craft and then build shit. then it gets more bonkers with the shit you can do with redstone/circuitry to automate minecart rails and shit to travel long distances for mines or basic travel. the game is what you make it. you can spend your days looking for diamond to make the best weaponary/armor, go around blowing up land with tnt, find wolves to tame which apparently became the rarest thing in the game or my friends just took all the fucking dogs since they have like a combined number of 100 or something and i have 5, build some crazy shit like the uss enterprise or something, it's a sandbox game focused around gathering i guess. then there's the whole issues of monsters coming to rape you in the dark
i've been playing a shit ton with my tf2 group in our own private server and it's pretty much a giant city now with rails leading to everyone's houses and shit. it's a nice getaway from the dumb fucks in tf2 sometimes and one helluva life waster. 24 bucks well-spent imo.
hi again