I also agree with the "golden rule" principle, but would add that it can depend somewhat on who asks who. Like if I'm wanting to go and need a partner, and I know my buddy's a little short on cash, I'll offer to take him and tell him not to worry about it. But if he's just hit a lick at the track and is dying to go, he might call me and offer to sponsor a trip. It all evens out in the end.