Screwed on prices

On 10/27/07 I brought my 2002 Audi TT to Heinold & Feller for an oil change and spark plug change. They charged me $28.22 for each spark plug without labor just parts. THese plugs, (NGK PRF6Q) are much cheaper. The highest price I found was $14.58 each at the Audi dealer. I called and spoke to Mike who said that is what they paid. He also stated that everybody has a mark uopp on parts. Which I agree with, but not doubling the price. I said after many years of going there myself, my wife, and my daughter will never come back.