buying cars

well my wifes friend got a new car today we looked at 4 lots and ended up back at the lot she got her last car from. Well they had a beauty for her they wanted $2750 for it and I talked them down to 2000 even in cash small unmarked bills. My brother the ASE master tech wasn't so sure about it but she couldn't live  without it. There might be a problem with the engine but hopefull she can get at least until november outof it with out any majior repairs.