> We have a huge problem in the office right now in that we don't have any mechanism to pay each other digitally for things like lunch - seriously!
Have you considered running an internal credit system? Those who pay for other's shares of a given lunch get credits for those, and those whose lunch is paid for get debits.
When a group of people go to lunch, the person with the persons with high debt should pick up the tab.
Once a week or once a month or something, people should bring cash to settle their debt, with the cash then distributed to those with credit.
We almost did that at an office I worked at...but got bogged down in bikeshedding other features. In particular, our biggest lunch problem was not settling the bill. It was agreeing where to go to lunch. So some people wanted the lunch manager to also handle that, and wanted to do it in a way that was fair.
How to do it fair is not obvious, and no one could agree on the solution.