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 - $15.25
Lightly Played - $14.50
Moderately Played - $11.50
Heavily Played - $9.25
Damaged - $6.25
Near Mint Non-English - $15.25
Lightly Played Non-English - $14.50
Moderately Played Non-English - $11.50
Heavily Played Non-English - $9.25
Damaged Non-English - $6.25
Foil Prices
Near Mint Foil - $33.50
Lightly Played Foil - $31.75
Moderately Played Foil - $25.25
Heavily Played Foil - $20.25
Damaged Foil - $13.50
Near Mint Foil Non-English - $33.50
Lightly Played Foil Non-English - $31.75
Moderately Played Foil Non-English - $25.25
Heavily Played Foil Non-English - $20.25
Damaged Foil Non-English - $13.50