There are a lot of specialty businesses that operate on an anti-customer model, the only thing that keeps them in business is the fact that they have very little competition. My dad is an optician, he sells and assembles glasses and basically makes everything actually function in the store. He has worked for employers that insisted on screwing over customers as much as possible, resulting in the customer never coming back. The only reason these places stayed open was because they were the only eyewear store in the area, and sometimes these places still went under. Apparently a lot of business owners who really have not gone to business school or learned about customer relations, treat their customers like garbage. When you take a business like a gun shop, which is a difficult business, you can expect some of these owners and employees to be somewhat jaded by years of irritating customers, and if they act nasty towards customers, the customers will be nasty back, and they will only become more nasty to the customers, thus becoming miserable, arrogant people who have no desire to deal with customers. These just aren't the right people for the job, and the places that have such employees and owners can only hang on by being the only one around. My advice with these places, is to find out the cost of what you want, and know exactly what you want before hand. If they have it at a price you like, just walk in with cash, say "I want this", do the paperwork, hand over the cash, and be done. Otherwise, go to one of the many retailers that receive so much praise on this forum, and as long as you're not a real pain to them, they will be great to deal with and happy to help you.
As far as finding a reasonable price for a firearm, Gunbroker is a good way to gauge the going rate, most local retailers will have slightly higher prices, sometimes significantly higher, occasionally lower. Don't forget about the price differences with shipping, transfer fees, credit card fees, and tax. If you look around some other online retailers like AIM Surplus, J&G Sales, Classic Arms, Bud's Guns, etc, you may find pretty low prices that may often times save you quite a bit if you buy online and do a transfer, though shops might not like doing a transfer on something they already carry, unless the transfer fee is greater than their markup. Cash and credit prices are often different because a retailer has to pay fees and taxes with credit transactions that they do not have with cash. Just remember to always keep receipts together in a safe place, since you don't have any other proof of the purchase when using cash. A credit card or bank card may be the better choice for an expensive firearm purchase just for the added security of having a financial institution behind your purchase. I still usually use cash on anything I buy in person though.