Performanceknls might be able to help you. She is located in NM. $400 is about the going rate; additionally, a cheaper ear crop may not always be a quality crop. Lisa (performanceknls) crops her dog's ears so PM her.
There is not good vets in New Mexico except down in Las cruses. I drive from Los Lunas to Las cruses to get my dogs cropped and the cost is about $250 per dog. He does a great job his name is Dr Schumacker. I just got my whole litter done by him last year and he did them perfect!