Uranium Ore

Uranium Ore
For real. You can actually buy low radioactivity uranium ore! Totally legal and legit. You no longer have to buy from Libyans in a parking lot!
 
$39.95
Via amazon.com

Marty McFly Hat

Marty McFly Hat
Marty, you've got to come back with me! Even if you can't get back in time, you can pretend with this spiffy hat from Back to the Future 2.
$19.77
Via amazon.com

Flux Capacitor

Flux Capacitor
This is what makes time travel possible; the Flux Capacitor is the crucial component of the Back To The Future time machine, aka the awesome DeLorean! One of the best-known props from the trilogy and sports authentic-looking lighting effects. 
$319.00
Via amazon.com