You shouldn't be having unprotected sex if you don't want a kid. Plan B is pretty efficient as long as its taken within 72 hours of intercourse, but its still possible that she could be pregnant. I suggest using protection, or better yet, having your girlfriend get on birth control.
I haven't played gaia in a LONG time but when I did play, I remember being able to sell them as well as the boots and cans and stuff that you get when you fish at the same place you buy bait and fishing poles.