Nintendo Virtual Boy Baseball Hat purple/black:

Nintendo together with Blockbuster Video stores organized the "Must See 3D Sweepstakes" competition before the date of September 30 1995, the prizes were: 10 grand prizes being VIP trips to Hollywood, 250 first prizes being VB systems, and 2,500 second prizes being Nintendo VB Baseball hats with the VB logo (purple, black, red) on the front.
Retail value US$12,- (see add in the US Nintendo Power magazine #76, last page).