You don't get a solid answer because there isn't a solid answer. It depends on what year and model car you want,condition of car you will accept, location, auto or manual transmission, how much repair work you can or will do.
All you have asked for is what is the cheapest car you can get. Supply a little more information about your needsand expectations. The cheapest car may cost less than $1000 but it may not run.
You should be able to find most of the information by doing a search. Not trying to put you off but your question is like asking how long is a string? It depends. Try rewording your request for information
to get better advice.
Oh, welcome to the forum.
Clifton
