Here are a few tips from me that I wish I had put into practice instead of losing control to pure excitement and driving off with the car as fast as I could instead of asking some very basic questions that could have saved me $$$ further down the line.
Check the rotors and brake pads on the car if there about to go drop the price same thing with the tires.
Check service history find out what's been broken and fixed.
And the most popular thing you can do is pay a mechanic to pre examine the car for you before you buy.
Watch this video for a few more tips.
Porsche boxter fifth gear - YouTube
And good luck.