U.S. antitrust regulators have given clearance to a proposed $483 million merger between Sprint Nextel Corp. (S) and Virgin Mobile USA Inc. (VM), according to a notice released Monday by the Federal Trade Commission.

Sprint announced in July it would acquire Virgin. In buying Virgin Mobile, Sprint is taking over one of its wireless resellers and gaining a pay-as-you-go option that rounds out its low-end offering.

Sprint has struggled to keep its more lucrative contract subscribers and has turned to its Boost Mobile unit, which provides a cheaper service without contracts, to shore up defections.

As consumers tighten their belts amid an economic slowdown, more people are gravitating toward cheaper prepaid plans that don't require lengthy service contracts.

The deal could be subject to review by the Federal Communications Commission.

FCC officials weren't immediately available for comment, but independent analyst Stifel Nicolaus said in July that Virgin Mobile holds a small number of international wireless licenses, which would need to be transferred to Sprint to complete the deal and also give the FCC the jurisdiction to review it.

The FCC last year cleared Sprint's purchase of Clearwire Corp (CLWR).

-By Fawn Johnson, Dow Jones Newswires; 202-862-9263; fawn.johnson@dowjones.com