BEND, Ore. (AP) _ Dan Piske owns a stamp collector's dream: a rare misprint that could be worth more than $1 million.

The U.S. Postal Service, which issued the stamp by mistake, wants it too. Its offer: Twenty-nine cents and a commemorative coffee mug.

''Let's just say I told them that probably wouldn't be in my best interests,'' said Piske, a self-employed draftsman and amateur stamp collector.

Piske said he's been hounded by collectors since he bought the stamp.

''It's just been absolutely crazy. It seems like the whole world has been calling me,'' he said.

The stamp was included on a sheet commemorating 20 heroes of the Old West. It could fetch more than a $1 million at auction because it bears the name of cowboy Bill Pickett but actually depicts his brother, Ben. Misprinted stamps are often prized by collectors because of their rarity.

Bill Pickett is credited with inventing the rodeo sport of bulldogging, or steer wrestling, after imitating the way a dog brought down a calf by biting its upper lip and flipping it to the ground. He died in 1932 after being kicked in the head while breaking a colt.

Pickett's family members spotted the error on the stamp a week ago and notified postal officials. It was the first time in 147 years that the Postal Service has issued a stamp carrying an incorrect image. All 250 million sheets in the series have since been recalled.

Bend is the only place in the country where the stamp was mistakenly sold. Postal officials there told Piske they would buy the stamp back - for face value. They also offered to throw in the mug.

''We told the individual that an error had been made and would he be willing to return it,'' said Azeez Jaffer, manager of the Postal Service's national stamp program in Washington, D.C.

Piske bought the sheet of stamps to mail Christmas packages to his sister in Georgia.

Their father, a retired Postal Service employee, saw the stamps and told his son they weren't scheduled for public release until March 29.

''It was only when my Dad called me and asked me where the heck I got them that I realized they must be something special,'' he said.

At least one other copy of the stamp was by sold, but it apparently was used to mail a letter. Whether that would hurt its value to collectors was not immediately known.

The exact number of stamps that were mistakenly sold won't be known for certain until the recalled sheets containing the misprint arrive at the agency's main distribution center in Kansas City, Mo.