Go to an online Persian rug retailer. These websites include 1001 Persian rugs, Rug Man, and Pak Persian Rugs.
Go to the library or book store and read a Persian rug price guide, such as "Oriental Rugs: A Buyer's Guide."
Go to an antique convention or flea market.
Read a magazine on Persian Rugs. Go to the Jozan website for a list of Persian rug magazines and more information on rugs in general.
Go to an Oriental rug conference or fair. One of these conferences is called the ICOC or The International Conference on Oriental Carpets. This is held every four years at different locations around the world.