That was quick ...
Brand new autographed O.J. Simpson memorabilia has already hit the market -- just 10 days after Juice signed a bunch of helmets in a secret Vegas hotel signing session ... TMZ Sports has learned.
Steiner Sports -- one of the biggest memorabilia dealers in the business -- just posted two new signed Buffalo Bills helmets in the "new arrivals" section of their website. One is selling for $400. The other, containing O.J.'s Hall of Fame year, is going for $450.
