Depends on the girl. Ideally, you want to give 'em something three times the value of what they gave you, but so long as it's at least double, you're fine. But your own feelings are part of it too, same as theirs on Valentine's day. Meaning most of your return gifts are gonna be obligations.

So for them, probably cookies or white chocolate, maybe inexpensive jewelry if you wanna go that far. Like for a girl who's more than an obligation, but not someone you have feelings for. [A friend, Fuyuhiko. The word you're looking for is friend.] For Sonia though you'll want to go with something a little more...personal.