Chad Johnson I Dropped $8,000 on Marty McFly Shoes!!

12/22/2012 6:30 AM PST

Chad Johnson -- I Dropped $8,000 on Marty McFly Shoes!!

Chad Johnson just bought himself an early Christmas gift ... those AWESOME Marty McFly shoes from "Back to the Future" ... and it only cost him $8,000!!!

Sources close to the former Miami Dolphins player tell TMZ ... Chad (an avid shoe collector) found the sneakers at ATC Miami -- a high-end sneaker shop in Miami Beach -- and decided he HAD to have 'em.

We're told the shop wanted $10k for the shoes ... but Chad managed to haggle his way down to a reasonable $8k.

It's a helluva deal -- considering rapper Tinie Tempah dropped $37,500 on a pair of the Nike kicks during a charity auction for the Michael J. Fox Foundation last year. 

For the record, Nike only made 1,500 pairs of the shoe ... and we're told Chad has yet to decide if he'll actually wear them out ... in the future.