For the last few months, I've used https://www.getcroissant.com/ which is ClassPass for co-working spaces. I like being able to bounce around different spaces, as well as use it in cities all over the world.
I saw their pricing and don't know if the hourly model makes sense for co-working. For comparison I've used Deskpass (and have been pretty happy with it so far). You book by the day - for $200/mo you get 20 visits (and unused visits rollover), which comes out cheaper than Croissant.
