The card table Claire Wiegand-Beckmann bought for $25 proved to be a good investment. The table, an 18th-century gem, was sold at Sotheby's yesterday for $541,500.

''I'm flying,'' Ms. Wiegand-Beckmann, 71, said after Sotheby's annual Important Americana furniture and folk art sale.

The retired teacher bought the table more than 30 years ago at a garage sale and displayed it in her home in Bergen County, N.J. ''I've always been a garage-sale enthusiast, but I never expected to get this much for anything,'' she said.

Israel Sack Inc., a New York dealer of fine American antiques, bought the table, which was one of six made by the Boston furniture maker John Seymour & Son. The meticulously constructed table has its original finish and is considered to be in good condition.