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 - $16.75
Near Mint Non-English - $16.75
Lightly Played - $16.00
Lightly Played Non-English - $16.00
Moderately Played - $13.50
Moderately Played Non-English - $13.50
Heavily Played - $10.00
Heavily Played Non-English - $10.00
Damaged - $8.50
Damaged Non-English - $8.50