Gauntlet of Power 255/301 (The List Reprints)

As this artifact enters, choose a color. Creatures of the chosen color get +1/+1. Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

NM - $9.60
LP - $7.70
MP - $5.80
HP - $3.90
DMG - $2.20