Frozen crab legs are found in many retail stores, including Meijer, Walmart, Kroger, Sam's Club and Costco. Prices and package sizes vary from store to store. Packages start at one pound and go up to 20 pounds, with prices between $13 per pound and $30 per pound, as of 2015.
The bulk, wholesale stores generally carry much larger packages of crab legs, so expect to pay a significant amount of money there. However, many local stores put out weekly ads with their sales prices listed, so there is a good chance of finding crab legs on sale if you watch the ads carefully.