First of all, $20??? When did it go back up? That is great news. For awhile it was like $7. At SFO, you couldn't even buy a snack for that much.
I've done 2 things
1) when my friends all took an overnight VDB, we each got $60 (3 meals), so in total we had $240. We used some at the hotel for dinner, then had $150 left when we came back to the airport. We bought tons of snacks for the trip, then had about $50 left and just told the people in line all their food was comp'd until it ran out. It was a pilot first behind us so we were happy about that
2) At SFO, I bought a smoothie for a gate agent (not the one who gave me the VDB...that would be a conflict of interest I think)