If youf damages are less than $7,500, then your best bet would probably be to file a small claims court claim. It's generally not economical to hire an attorney for these claims. You can find forms and instructions for filing a small claims case at the Colorado Judicial website.
I don't practice in your jurisdiction but some general rules apply to all lawyers. In a criminal case, the "victim" does not need to hire an attorney, as criminal cases are prosecuted by the state; private attorneys have no standing to appear before the court, other than the defendant's attorney. Civil cases are billed to the client in several different ways. Depending on the nature of the case, it could be a flat fee (an agreed upon amount for handling the case regardless of outcome), an hourly rate (an agreed upon amount for each hour or poetion thereof that the lawyer works on the case, regardless of outcome) or a contingency fee agreement (under which the attorney collects no fee unless money is recovered). I hope this helps.
Mr. Harkness is right. You have not stated the amount in dispute. Also you have not stated whether there is any warranty in your case. Some shops have no warranty when they perform any type of repair. You do have to do some type of cost benefit analysis. Clearly the shop owner is not reputable as you state there are other dissatisfied customers. Check your repair or sale contract regarding your right to sue without first having the dispute resolved by any alternate dispute resolution method like mediation or arbitration.
Your matter appears to be civil in nature. You have to look at attorney services as an investment and not a cost.
Also check if the shop owner is a member of a trade association or BBB. If yes, file a consumer complaint with them. Sometimes, your dispute could be resolved through this method without having to go to court.
Remember, doing proper research before doing business is wiser and cheaper. Also the cheapest shop is more expensive in the long run. Consumers must pay an additional price for reputation, integrity, honesty, reliability, after service support and service.
Worst case, you can learn from this situation and make a better and more informed decision in choosing a service provider or merchant. Consumer must learn that price must be the last and least important factor in making any purchase decision.
Sometimes it may be wise to cut one's losses and move on if the cost and uncertainty is more than the benefit.
You may not like what this answer but sometimes reality is better than an illusion.
Civil litigation can be uncertain, time consuming and expensive.
Best of luck