You could always get in to bed with pubs and bars and offer a "order a tab" form on your site. Or hell, make the tab city wide. User puts a 50$ tab on, your sys

You could always get in to bed with pubs and bars and offer a "order a tab" form on your site. Or hell, make the tab city wide. User puts a 50$ tab on, your system integrates with the pubs/clubs who buy drinks against the tab and you take a small percent.