Don's Sports Shop in Scottsdale has a huge selection. They have some for serious $, but I'm sure they have some in your price range. They are good folks. I bought my Benelli Legacy from Don's ... the price was right and they have always been there when I needed something. Don's was also really good about letting me handle the guns to see which fit I liked best, etc.
For more, check out Arizona Sportsman (I've only been to the one in Mesa) ... not the friendliest store in the world, but they have a big selection, and a lot of O/U in the sub-$2K category. At AZ Sportsman, you have to pry them away from their pals, and interrupt the conversations about lift kits for their trucks, etc. They hand you the gun and walk away.
Elber: There is a guy advertising Beretta and Browning O/U's on GunBroker.com and he gives a Phoeniz address. His name is Seto and he has what appears to be some really cheap prices. Don't know anything about him. If you decide to deal with him, I would like to know more before I order a gun from him.
I was just at the new Sportsman's Warehouse by I-17 and 101 (next to Costco). It opened a couple weeks ago and they have a great selection of O/U. I was surprised how low their prices are (Ruger Red Label $1069 etc). The service is outstanding too.
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