How about another option - rent a large space once a week for the weekly meeting day. This would require everyone to vote and agree on the meeting day, and maybe the day can be revisited/changed once a quarter. While its expensive to rent meeting space 4 times a month, it might end up being cheaper/more flexible than a dedicated office. It also allows the opportunity to meet up in cooler locations or outdoor venues on nice days. Again this depends on the type of work needing to be done, but could this work?