Basically, materialistic people will push you to pay (expect it). Sometimes you can tell by what they wear or if they ahve lots of expensive things or only look for expensive things. Their taste in things will show you. But if your just basing it off the fact of a couple dates and you paid that's really not enough. I mean ask her the types of things she likes, or if you guys go somewhere, even if you have the money when it comes time to pay... ask her if can she help pay. Like if the bill is $20 ask her if she has $5 or $10 because you don't want to break a bill (if you don't) and if she gets offended you'll know she expects you to pay all the time.
If you can't handle the thorns, don't crave the rose!!