what I did once, I looked up some prices on the internet, vwaftermarket.com back when I had a vw, and took the prices I found to a local shop. I told them if they could beat the price I would buy from them and they did. I hate negotiating so that was pretty simple and it worked.
ofcourse on the internet you have to pay for shipping and at a local shop you have to pay taxes so it pretty much evens out.