Don't worry about asking beginner's questions, that's one of the main points of the forum, to share information and help everyone progress
As the others have said, it's best to get a spare set of wheels as there isn't normally a tyre changer at most drift days. How much your tyres wear really depends on how light your car is, how long you're driving for and how rough/abrasive the surface is.
Unless the surface is really abrasive and you have very soft tyres, you can normally get away with keeping your normal fronts on, but they will get scrubbed at the edges...
Sticky front tyres and crappy back ones are good to learn on, but as you progress, you'll find better tyres on the rear can be more controllable and smoke a hell of a lot more
Last round at Silverstone (a very grippy, but not a rough surface) I drove home on the same tyres I'd been using all day, but I didn't get that much tracktime that day and they were borderline......
Last thing to remember is to get some heat into the tyres before you really start to give them hell. If you go straight out and thrash a set of cold tyres, the outsides will heat up a lot faster than the insides and big chunks of tread will peel off...... not nice...