Some people just forget to say thank you. This does not necessarily make them a bad person. When you feel that a "thank you" you could just say "you're welcome". If she responds with a thank you then she jst needs some training and you can keep her. If she looks at you as though you are nuts then she is a princess and you should dump her.

I can't help you with the paying thing. I can't say as I have ever gone out with anyone for several dates where they had not at least offered to pay for something.