It does really depend a lot on the car. My brother's Subaru has 270k on it and runs like new. My Mazda has 140k on it, runs like new. My dad's Ford has 220k on it, runs like new. My mom's GMC has 70k on it and the engine has a knock and it goes back to the dealer at least once a year
I don't think $2100 is a bad price for a Supra, people go crazy over them so they hold their value very well. It's got a good powertrain, but I don't like the way they handle in stock form. If it runs and drives well right now go for it, drive it stock for now then upgrade it properly when you get the money.