Mate we've all done that .I saw a new one i wanted only 6 weeks ago , sold my car on autotrader and the one i saw was sold ,lol. Just have a look about , get to know what a good car should look like and what a car thats been hammered looks like . Maybe even take a test drive in a couple .
Just don't jump at the first car you see when you get the cash together cos it looks nice n shiny . Take a mate with ya , cos a second pair of eyes might spot something you've missed when you've already made your mind up its the car for you .