I think you're fighting for the wrong clients. Let him have the $5-10 deals and you go after the higher end clients. Besides the $5-10 clients won't be that loyal. You'll steal them until someone beats your prices. That's not the best type of clients to shoot for.
I know its tough to see him washing cars and your not. Been there. Think about how hard they'll be working in the summer heat for 5 bucks. Not worth it to me. Heck if you're looking for extra work and have some spare time, call a few regulars and offer a free wash as a customer appreciation day.
The best advertising I had was with a brag book of my work. I would show that off to potential ups (clients). They would see the before and after pics and schedule a service. You have to talk to people. Make them interested/excited about taking care of their vehicle. More often then not, when I tell someone I detail cars, they ask about how to fix a specific problem on their car or say "yeah I've been meaning to get my car detailed". There's an up right there. Find their hot button.
If the joker across the street offers a wash for 5 bucks, offer a wash and vac for 7 bucks. Don't just match his services and prices. Add more value and service to a higher priced package. People will pay more if they're getting more. I'm not saying to set sky high prices. Not yet at least. You have to grow a business. My first summer I was giving details and time away. That winter my prices went up. I had made more in sales by the end of the next spring, than the entire previous year in sales. I had a growing network and word of mouth advertising. I hooked up with a few local business and worked out deals with them too. All that's over now since I moved to NC. Although I've already generated interest locally by planting seeds.
Good luck. Drop me an email sometime, I'd like to find out more info about your business plan and model. For example... Are you a car wash or detail shop? Do you offer any other add on services (PDR, leather repair...)? Who is your target market? What kind of time can you give to a detail shop now (in school full time or full time job)? Stuff like that. My apologies for the filibuster.