10% should be your minimum. Invest in a decent ad in the real phone books (not these little community ones). Newspaper advertising attracts the cheapest of the cheap. Direct mail is shredded money. Coupons eat what little you would have left after you grant the discount on your coupons.
All major Yellow Pages offer the option to link your ad to their Internet advertising. An example that is well known is www.Superpages.com.
We switched to this option with our Verizon Yellow Pages ads and response took off like crazy. Granted, they also generated more calls from junk salesmen, but those calls are usually pretty easy to screen.
You have to spend money to make money. Granted, up to 20% is the best, a small shop can't support that kind of volume generated. Unless you have a full office staff of knowledgable people who know what they are talking about and can give estimates over the phone, stick with 10% for now. The last thing you want to do is blow 20% which generates more activity than you can handle. You also don't want bad press from people who had to leave messages and never heard back from you. There's only so much you can do in a day. Spend accordingly and expand gradually.
[This message has been edited by EV607797 (edited 11-28-2006).]