The Streetcar brand will be retired at the end of October, as nearly all Streetcars have become Zipcars. Rather than joining Streetcar, you should join Zipcar, and gain access to their huge fleet of cars.
You still get all of the same amazing prices and member benefits as with Streetcar, but you get more cars.
What's more, you can now get a free driving credit of £25 (instead of the usual Streetcar £20), when you signup via this link
Just click on the link, register, and once you've paid your membership fee and verified your details, you'll receive £25 worth of free driving, that's up to 4 hours worth of free driving in a brand new car!