I like theory's idea. I'm having a hard time imagining what I'd generally want to do in response to it. I do think, tough, that it's unfortunately political and will rarely help you with the actual gaining effect (it essentially lets other players give you a card, that they want, turning it into a one shot lab. Hm, actually, I guess any $3 or $4 will often be accepted in a 3+ player game, but again, it is still political).
I feel like I should mention, my currently in playtesting fan expansion has a card called wedding, which currently looks like this:
Wedding
Action - $4
Choose one: Trash two cards. If you do, gain a Duchy, putting it on your deck. OR Trash two victory cards. If you do, gain a Gold.
I'm not 100% happy with it currently, but the thematic idea is that you combine the stuff of you and another person (trashing two cards) and get something expensive out of it. Mechanically, it's main problem is right after the first shuffle, where getting a gold while trashing two estates is super powerful while trashing say an estate and copper for a duchy on deck is meh.