I go to Burlington Car Wash on 3A(http://www.burlingtoncarwash.com). It's a bit of a drive, but it's worth it. The place has two no-touch machines that do a great job on the cars. They use filtered water = spot free dry. I think a basic wash is like $8 and it literally takes like 2 mins.
Check'em out:
310 Cambridge St
Burlington, MA 01803
(781) 272-1032