26 U.S.C. § 9819

A group health plan shall offer price comparison guidance by telephone and make available on the Internet website of the plan or issuer a price comparison tool that (to the extent practicable) allows an individual enrolled under such plan, with respect to such plan year, such geographic region, and participating providers with respect to such plan or coverage, to compare the amount of cost-sharing that the individual would be responsible for paying under such plan with respect to the furnishing of a specific item or service by any such provider.