Our nights are free entry so, technically speaking, you don't have to buy anything in order to perform!
However, we do encourage performers to buy food and / or drink at the venue - even if it is just a soft drink (and certainly not to bring in their own food or drink from outside).
This is for the very simple reason that, if performers don't spend any money at the venue, the venue will close the open mic!
(they are a business, so it must make business sense for them to spend their resources on having an open mic!)