Sold a used car and it broke down what rights do i have?

if you bought it as is there is nothing you can do, unless the one who sold it to you wants to nice about it and help you out, alot of used car lots only fix them up enough for them to last a short time, unless you bought it on credit then they will fix it or let you get another one, really depends on the place, that's why you have to be careful when buying a used car, of course it also can happen with the best of cars, even new ones can start having major problems, with a new one you can fall back on the lemon law, which is still in effect in almost all states