$5 Car Wash? I'm in! I regularly get my car washed at Tidal Wave and it sparkling clean when I'm done. You start with a DIY debugging station, proceed to the automatic car wash, and then vacuum the inside for free. No time limits on the vacuums.
My only suggestion is to go on a weekday. The place gets crowded on the weekend and it gets hard to park the car to use the vacuums. Still, I'm normally in and out in 20 minutes. Plus, you can reward yourself for your thrift and efficiency with a Krispy Kreme donut-there's one in walking distance of Tidal Wave.