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.)
"Hup, two, three, four,
Dunno how to count no more."
—Mogg march
Near Mint - $17.00
Lightly Played - $13.60
Moderately Played - $11.90
Heavily Played - $10.20
Damaged - $8.50
Near Mint Spanish - $17.00
Lightly Played Spanish - $13.60
Moderately Played Spanish - $11.90
Heavily Played Spanish - $10.20
Damaged Spanish - $8.50
Foil Prices
Near Mint Foil - $33.40
Lightly Played Foil - $26.70
Moderately Played Foil - $23.40
Heavily Played Foil - $20.00
Damaged Foil - $16.70
Near Mint Foil Spanish - $33.40
Lightly Played Foil Spanish - $26.70
Moderately Played Foil Spanish - $23.40
Heavily Played Foil Spanish - $20.00
Damaged Foil Spanish - $16.70