Baird Brothers on N Valley Mills drive. It's a drive through but isnt just a power wash...like Genie car wash, but you don't get out of your vehicle--you put it in neutral and it pulls you through. Cheapest wash is $4. Vacuum cleaners are free.
There is a place on Hewitt Drive across the street from Kwik-Kar that is that same concept...they hand scrub the wheels and spray off the car before you drive through..you do stay in the car. The vacuums are free and I think I got the super and it was $10.
I use the place by Midway Middle School. I don't do the tunnel wash, although I've heard it's good. It's $5 for 20 minutes slef wash and free vacuum for a long as you'd like.