[lastchance]

Definite agreement here. If your GF's family celebrates Xmas, you have to thank them for taking you in, and because they mean something to your GF.

Don't be lazy (unless you really don't have the time), go out and buy something nice for them, all of them, including your GF.

Don't buy something too nice though, $10 a gift sounds about right. Just something to increase their opinion of you, and you'll definitely get a big "thank you" from your GF.

Be thoughtful, be nice. It's cheaper, and it's a good thing to do.