Hal is immediately interested when David accepts the challenge.

"Hey, if you can pull it off I'll buy you all the drinks you want."

And then he's immediately checking his pockets to make sure he can actually back that up. There's enough for a few drinks, but not enough for a free for all. There's a depressing though that this is probably the same amount of money he has on Earth too.

"Okay, as many as I can afford."