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 - $13.500
Lightly Played - $10.800
Moderately Played - $9.500
Heavily Played - $8.100
Damaged - $6.800
Near Mint Spanish - $13.500
Lightly Played Spanish - $10.800
Moderately Played Spanish - $9.500
Heavily Played Spanish - $8.100
Damaged Spanish - $6.800