What's the average cost of an attorney for a DUI case.

Good question. It differs from state to state and from area to area. It's also uncommon for attorneys to reveal their charges and fees. Quite often attorneys charge based on the nature of the case and the degree of difficulty, along with ability to pay, things like that. The best way to tell, in your area is to shop around for a good attorney. Talk to at least three that offer free consultations. Do not give them the impression you are retaining their services. Let them know, upfront, you are shopping for the best attorney for the most reasonable fee. This is not common, but something I believe more consumers should be doing. Then you will get a good "feel" for different attorneys that may be able to help you at a reasonable fee. I know that this doesn't answer your question, precisely, but I hope this helps.

Anywhere from 3-15k depending on complexity of case, experience of lawyer, and if you go to trial or not.

My colleague's range of $3K-$15K is about right on the low end and perhaps a bit high except for an exceptional case. I routinely challenge the blood work and charge about $3,500 to $4,500 depending upon various factors.