Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)
Near Mint - $29.40
Near Mint Non-English - $29.40
Lightly Played - $26.50
Lightly Played Non-English - $26.50
Played - $20.60
Played Non-English - $20.60
Heavily Played - $17.70
Heavily Played Non-English - $17.70
Damaged - $14.70
Damaged Non-English - $14.70