The local shops here seem to have a very open policy - I know of two that have classroom space that they allow anybody to use. Basically if the class space isn't currently in use, you're welcome to bring your machine, bring your friends, set yourself up and use the space! One shop will also rent a "classroom" machine to you for a $5/day fee if you need it, but no fees if you bring your own. One of these shops is very near where my guild meets and one of the owners (?? Key employee, anyway) is in our guild, so we tend to use their space quite a bit and they're all very friendly about it.
It's a smart policy...I don't think I've ever been there on a day where at least one person didn't realize they needed something and went and bought whatever it was.