I need help on a gift to buy my girlfriend!?

my girl and I have been dating for a little, and i can tell that i really love her. she is a sweetheart and is always buying me little gifts, but i dont know what to get her? i wanna get her something cute and meaningful. my limit is $40. and idk about jewlery, cause she not to much of a girly girl, but still looks pretty. she 18, half mexican, and very pretty. she likes to draw and play guitar. i was thinking about buying a cute picture frame,with a few photo slots, and puting pictures of us in it, but is that good enough?? if youu have other suggestions, that would be big help!! please!