Cheap car

As some of you may or may not know my step daughter, son in law, and grandaughter moved in last weekend. They have recently fallen on hard times and he is waiting to go to boot camp for the army in 3 months. Well they need a car now that they are living " Way out in the sticks" http://www.bassboatcentral.com/smileys/Laugh.gif . they don't have a lot of money somewere in the $500 range or so. They are not expecting anything extravigant but needs to be reliable. Thanks in advance for any help.