The context of the following conversation is Ash ordered a big sandwich at the deli because they are very hungry.  Ash put $3 in a tip jar.:
Ash says Let's go to the deli; I'm starving..
The friend responds Okay, sounds good..
Ash responds And I'm paying for both us with my bonus money..
The friend responds Thanks for buying me this sandwich..
Ash responds Not only that, I put $3 in the tip jar..
The friend responds Get a little bonus and now you're the big spender--thanks again..