The saga of a beleaguered Billy Carter ended here at a hot, dusty public auction today when the ex-First Brother sold off property, including his gas station, to pay the tax man.

Also put on the auction block were assorted lots, the frame house where and wife Sybil raised five children and a softball field where he onced pitched in a "Redneck Power" T-shirt against reporters and a president.

Afterward, Carter tugged on a filter tip under the auctioneer's tent, relieved to have earned enough money to settle accounts with the Internal Revenue Service and local bankers, and said his last goodbye to Plains. He was off to Haleyville, Ala., 110 miles and a world away, to seek a "clean break" and start a new life promoting homes for a large construction company.

"I won't miss Plains at all," he said, calling it "a sad day and a good day. Some people will be glad to see me go. Some I'll be glad to leave.

"The only people I hate to leave is my pastor and my mother." Miss Lillian, 82, undergoes surgery Monday for a malignant lump in her breast.

Carter got more than $160,000 from the auction and the private sale to the city of a lot behind the station. It was enough, he said, to pay $70,000 he owes the IRS from a 1978 tax debt and about $30,000 to local bankers who have threatened to foreclose on his 7,700-square-foot, ranch-style home on 58 acres in nearby Buena Vista. o

Now, all he has left to settle is the $220,000 loan from Libya, whose government has been accused of promoting terrorism. Senate investigators concluded the 1980 loan was a failed attempt by Libya to influence the Carter White House through Billy, whose big-time dream of riches from potential oil deals with Col. Muammart Quaddafi may have helped thwart his brother's reelection.

He said today he has made substantial payments on a "six figure" bill from lawyers who defended him from investigations by the Justice Department and the IRS.

"The IRS gave us a lot of negative publicity [for the auction], but they're a negative bunch of bastards," said Carter, 44, his good-ole-boy persona blossoming afresh before TV cameras. "They tried to make an example of me . . . to embarrass me, but nothing embarrasses me."

For once, his brother and Billy agreed. "Billy was singled out for special persecution and attention because he was my brother," Jimmy Carter said.

The former president walked to the auction in tan pants and a sport shirt, seeking respite from the 90-degree heat beneath a shady oak, standing beside peanut farmers and their cur dogs aswarm with gnats. He said he "regretted" that his presidency had had a negative effect on his brother. "But he'd handled it well.

"I hate to see him go, but he has a fine position in Alabama."

Jimmy Carter sat in the back row and silently watched the bidding. "I hope everything brings too high a price for me to bid," he said.

As it turned out, Billy didn't need his brother's help. His gas station and softball field was snapped up for $54,000 by Roy Bertrand, 62, a self-styled gentleman horse farmer from Waukegan, Ill., and Reagan Republican who read about the distress sale in a newspaper.

He plans to convert Billy's gas station into one that pumps gasohol and has offered to lease the ballfield to the Chicago Tribune for $1 a year as a winter training camp for the cellar-dwelling Chicago Cubs, now owned by the Tribune company.

"God knows they need a place to practice," said Bertrand, in a flurry of humor that broke up the bittersweet day of nostalgia and change for the Carter clan.

Billy Carter's father had thought Jimmy would be a career naval officer and Billy would run the family peanut warehouse, but life hadn't turned out exactly that way.

Billy, a reformed alcoholic who has his personal furies under control and greeted reporters he once insulted with a smile, now starts afresh as a public relations man for Tidwell Industries in Alabama, where he expects to feel at home as a "George Wallace Democrat."

As autograph-seeking tourists in the crowd of about 300 swarmed around the Carter brothers, an organist played "Freight Train" while the auctioneer, J. L. Todd, singsonged away Billy's former home for $20,000.

Billy watched his youngest child, Earl, 4, lean against his wife's pink skirk and kick at the dirt. Sybil's blue eyes glistened with tears.

"It hurts," she said. "That house is where I raised all my kids. We lived there 15 years. It's still got the nails in the mantel from the kids' Christmas stockings and when I think of that, I want to cry. Those were the days when you didn't have to lock your doors."

And, then, in less than 45 minutes, Billy Carter's life in Plains was over. "We're out of Plains," said Billy. "How 'bout that?"