Reston, Va.--A business-to-business marketplace launched this week for telecommunications buyers. Simplexity.com, Reston, Va., provides neutral comparisons of business telephone rates across multiple vendors, including AT&T, MCI WorldCom and Sprint. Bill Bellows, COO of Simplexity.com, said the company will collect fees from the telecommunications companies in exchange for acquiring customers. Simplexity.com comes to market with a strategic alliance in place with Best Buy Co., Minneapolis, which plans to link to the site. Best Buy has also taken a $4 million equity stake in the Internet start-up.