Defroster, heat and A/C on. Try and keep your mats clear of ice and snow to keep it from repeating. RainX makes an anti fog spray for the inside windows, it’s pretty inexpensive and will help.

Good, fast or cheap, pick two!

If you find one that’s been well taken care of it should be pretty good, but at the end of the day you’re still looking at a car that is at least 20 years old. There will always be hoses, bushings, seals and other items that will be needing attention. That might be fine for a second car but maybe too much for your only vehicle. Also being young your insurance company will definitely charge you big money for a sporty vehicle.