I am not GP, but I search for cars for sale by owner on Craigslist using the following search string:

versa|fit|yaris|aveo|rio5|sonic|focus|elantra|soul|cobalt|leaf|mazda3|matrix

This will find you a small fuel efficient hatchback or sedan. Get familiar with kelly blue book and reply to sellers that have a reasonable asking price, then haggle. The last car I bought was a 2008 Rio with 100k miles for exactly $3000.