Tom Brady's signature is like GOLD -- the prices for a TB12 autograph are higher than ever ... DOUBLING in just 4 years!!
The Tampa Bay Bucs QB is holding a private autograph session for collectors and memorabilia shops ... and if you want his John Hancock on a Bucs helmet, you're gonna have to shell out $3,700!!!
Here are the current prices compared with rates from a TB12 signing back in 2017 -- back when Tom only had 5 Super Bowl rings (he's got 7 now!