Just to clarify, I agree with the sentiment of most everyone else. I bought a MK3 as my first car (not my first vehicle, mind you), but I have mechanical experience, and I spent a lot of time researching the Supra platform before I decided to buy mine. Even though mine may look like a bit of beater, it is mechanically, very sound.
If you don't have a good amount of experience wrenching on things, and know what problems to look for, and how to diagnose them, Supras can be headaches. Hell, ANY old car can be a headache, but the MK3 was an especially complicated and complex car for its time, which just means that more stuff can go wrong on it now.
MK3s require a lot of patience and compromise I'd say. It's not like an old Honda or Camry where you can just get in, drive it like hell and expect it to work all the time. Part of the reason why my car is as reliable as it is, is because I don't beat on it. I can drive in a spirited fashion, and I sometimes do, but constantly revving the nuts off of it, hard starting it, etc. will most likely guarantee the fate of that old 7M. Seeing as how you're still young (I'm young, but I take care of cars like I'm an old man), you WILL end up breaking something.
So, overall, unless you're ready to live with, and deal with a Supra, don't it.