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 - $27.00
Near Mint Non-English - $27.00
Lightly Played - $24.30
Lightly Played Non-English - $24.30
Played - $18.90
Played Non-English - $18.90
Heavily Played - $16.20
Heavily Played Non-English - $16.20
Damaged - $13.50
Damaged Non-English - $13.50