COLUMBIA — The Republican cast is lining up to audition for the 3rd District U.S. House seat being vacated by U.S. Rep. Gresham Barrett.

Four hopefuls already are gearing up bids to replace Barrett, a three-term GOP lawmaker who recently made a formal entrance into the 2010 race for governor.

From the state House, there's a fitness fan, a chicken sausage purveyor and an auctioneer. And one of the Senate's newest members, who survived a close race last year, said it's time for him to head to Washington. None of them can file for the office with the state GOP until March 16, 2010, but they're setting up exploratory committees, rounding up staff and putting out feelers for cash.

They'll need it. All of them expect the primary to cost at least $500,000. Traditionally, that has been the biggest challenge in a district where the GOP legend and late U.S. Sen. Strom Thurmond lived and is buried.

So far, the race has attracted:

--State Rep. Michael Thompson, who said Friday that he'll have an exploratory committee set up soon. Thompson, 34, is a salesman for the trucking company his father started in Anderson. He's a fitness buff sometimes seen in T-shirt and sweats after workouts at the House office building He's served in the House since 2001.

--Rep. Rex Rice of Easley, who already has a Web site set up and federal exploratory committee papers filed. A developer for years, Rice, 52, recently gave that up and became a partner in a business that makes and markets chicken sausage as a low-fat alternative to the artery-clogging stuff. He has been the loudest Republican advocate for years of increasing the state's cigarette tax from the nation's lowest at 7 cents a pack and has served in the House since 1995.

--Rep. Jeff Duncan, 43, of Clinton, who said he's not ready to formally announce but is seriously considering a bid. Duncan is an auctioneer and getting more business lately from banks unloading foreclosed property. Duncan is chairman of the Agriculture, Natural Resources & Environmental Affairs Committee and has served in the House since 2003.

--Sen. Shane Massey, 33, who is an Aiken lawyer and won his seat in 2007 after Democrat Sen. Tommy Moore gave up the job to work for the payday lending industry, beating Democrat Rep. Bill Clyburn by 138 votes out of more than 14,000 cast after a mandatory recount.

Massey has an advantage the rest don't. He'll have two more years on his term if he loses; for the rest, they're out of legislative jobs. That's not such a bad loss, said Duncan, who plans to go back to being a father and running a business if he is defeated.

As crowded as the field appears now, more are expected to pile in.

Barrett won the seat by beating five other challengers in the Republican primary in 2002 after U.S. Sen. Lindsey Graham stepped aside to run for his current position.

"It's a Republican congressional district with an open seat. Those things are not easy to find around here," said J.W. Ragley, the South Carolina Republican Party's executive director.

And there is the bonus of not having to knock off someone already in the office. "The easiest time to win a seat is when an incumbent isn't running," Furman University political scientist Danielle Vinson said.

Entering the race early gives people more time to raise money, Vinson said. The candidates all know how much of a problem that will be in the midst of a recession and with nine statewide races on the ballot, including governor.

"They're all fighting for the same donors," Vinson said.