is refuting reports that he's planning to charge fans $50 to take selfies at the Super Bowl ... saying it's "the dumbest thing I've ever heard."
Promo flyers circulated social media last week detailing Johnny's appearance at several Stadium Signature stores in Texas during Super Bowl week ... offering autographs for $99 and selfies for $50.
The Heisman trophy winner went to Twitter Thursday morning claiming the reports of makin' money off the snapshots are totally false ... and he's just looking to give back to his fans.
"Just had this brought to to my attention.