I wouldn't say haggling is out of the question, but there's always tact involved. A strong repeat customer who has purchased a bike compared to a guy just passing through town are worlds apart. The former will no doubt get VIP treatment and maybe even an unspoken discount if his purchases are in a great enough volume. At my current shop, we just ordered over a dozen trainers for a local club at a significant discount, and because the transaction went so smoothly and they are willing to pay for shipping we were happy to oblige. A small amount of bargaining was part of the deal and both parties are made happy.