In my area the pawn shop itself determines how you are going to do buying anything. One in my area has supplied most of my collection and I have bought a lot of items at this particular shop. It's clean, the staff is friendly and they are willing to negotiate and local law enforcement officers use this shop for many of their purchases. Another shop was always $50-$100 higher on everything and they were essentially asking retail new on used items and might give you a few dollars off while telling you what a steal you were getting. The guy there told me he would sell me a Bryco .380, the BEST gun out there now and throw in a box of shells for $299 plus tax! I just smiled and said, pass and walked out the door. Another shop in the area is where the druggies go, it's filthy, dimly lit and is sleazy.
I have bought most of my collection from a local gun/pawn shop. Initially they blew me off, they were not rude but they were not in the dealing mood. They had an excellent Browning Hi-Power LNIB that I really wanted and I paid right at $700 for it, the old guy threw in an extra magazine from their shelf of magazines. Once they knew I was a buyer and not one that looked but never purchased the deals started coming. Other than the Browning I never paid close to the price tag again. Sometimes they would make a fair offer right off the bat and I would take it, sometimes I would counter and they would take it, sometimes I would make the initial offer and they would take it, it varies. If we were too far apart I always thanked them and politely passed and waited. If the piece stayed on the shelf for two or three more months I would go back and make usually the same offer and they would take it. Other than firearms I have bought all kinds of other stuff from this shop. Lawn tractors, tv's, Ipods/Ipads, tools, bows, ladders, antiques and their separate jewelry shop has made me some smashing deals on jewelry for my wife and they repair items as well like bracelets and watches.
When dealing with a pawn shop just understand, you are buying used it may be listed as new and still in the original package but 99% of the time it had a previous owner, there are no warranties. Do your homework, inspect the items really well and look on the internet and local adds at going prices being quoted and sold prices. Have cash and if you make an offer be prepared to pay up if they accept it and always ask for the OTD Out The Door price which should include taxes. Once I saw a used Glock 17 in the counter, it was carried a lot in a kydex holster and the finish was worn but mechanically 100%. I made the comment to a worker I would buy that glock but its $100 too much and needs refinished badly. The next time their the main gun guy saw me and handed me the Glock and said $300 out the door, Merry Christmas, so I handed him some money and said put it in layaway. Also be prepared to walk if the price isn't right, don't be a jerk, just say let me think about it and pass. Being courteous goes a long way in any situation.