Hate to be that guy and normally I would NEVER recommend it,....but you sound like a prime example for a cheap lease.
If you have steady income and decent credit, go lease something for $99-199 a month for 2 or 3 years and you'll be better off in the long run when you both finish school and have a higher salary.
Again, I would normally NEVER recommend a lease but with your luck I see this happening. You buy a car for $3-6k and end up having problem after problem with it and never stop paying. YOu could lease a new car and pay the same maybe less over 3-years for a much better car. Now that is if you are working on improving your financial situation, school, education, etc...etc...it would only be temporary but again I don't know your story so just would throw the idea out...