Love /
Amount of money for gift (I have a girlfriend in Poland) [56]
Imagine that I have an American gf, and am sending her a Christmas card with a $20 bill tucked in...
This would be a very short-lived relationship.
1. A friend or a girlfriend?
A small, nice gift worth $20 (but not money!) is appropriate for a friend. But if you are talking about a relationship, then sending a $20 bill would be rather rude, especially considering the undertones present in you post (and that's why you got these replies).
2. If she is a girlfriend, then an acceptable minimum is a $50 gift card. If you don't have money, it's also ok to shop around for something inexpensive, but nice and unique (for me, a silver Navajo bracelet bought at Four Corners worked like a charm). Generally, don't expect that a "Polack" girlfriend (as you nicely called her) would have different expectations than an American one.
3. Women are expensive. This is a fact of life. Get over it. TANSTAAFL, and "you get what you pay for" apply. :)