Or you may just want to ask yourself "How hurtin' are these guys?" Bike shops are not a high margin business. If you have a good one and you want them to stick around, you might just ask yourself how much that 10% is going to mean to you in the long run, versus the 10% on every deal they do. My shop gives me free tune ups, they rebuilt my rear wheel 3 times for free, and generally have been great to deal with. Everytime someone in my family tries to buy a bike at Target I drive them over myself to make sure the place that really knows bikes stays in business.