Legal Question in Criminal Law in Texas

Pressing criminal charges is probably a lost cause here, since some money was paid and it seems clear there was consent for the buyer to take and drive the car. The only way that criminal charges could be pursued is if there were some way to show that at the time the money and car were exchanged, the buyer actually had criminal intent (specifically, that when she took the car, she never intended to pay another cent for it and was acting to defraud the seller). Typically, that's pretty hard to prove unless there's some kind of pattern of her having done similar things before, or if she was dumb enough to put it in writing--it would be nice to have an email from her the next day saying, "Guess what? Hope you don't expect to see me, the car, or any more money on this, cause that's not my real address, and you'll never find me--bye!", but you just don't see that too often.

Suing in small claims court might be an option, depending on the specifics, but without a written contract, it may be difficult to do that at all, much less to win and actually be able to collect any money on this.