One thing you could do that would be AMAZING!!! and would probably really make you appeal to anyone else that is out there is... donations to charities. Every wash or service done, $1-2 donated to bla bla charity.
I know when I start up, I'll be doing that. I used to do community service forever... and let me tell you: It's a great feeling knowing you can help people. When people see a business (especially independent) that would be willing to donate to a charity or foundation, it really makes a difference. If people see that, you could possibly have people who might be willing to back or offer contributions to help your business. Just my .02 cents.
Notice: If this offends anyone, I apologize if I've offended you in anyway. I would never use charity for business purposes only, I think it would be a good opportunity to offer.