Information:
To advertise EarthBound, Nintendo of America sent out a poster to retailers to display in their windows. Two kinds of posters were made: A large 27" X 40" poster and a 22" x 28" fold-up poster. This was never sold in stores, and interestingly enough it has a Universal Product Code. This poster is extremely rare as most stores at the time would just throw their advertising materials away at the end of a promotion.

Images:


Thanks to GotARiverFenixEP for some pictures!