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 - $15.900
Lightly Played - $12.700
Moderately Played - $11.100
Heavily Played - $9.600
Damaged - $8.000
Near Mint Spanish - $15.900
Lightly Played Spanish - $12.700
Moderately Played Spanish - $11.100
Heavily Played Spanish - $9.600
Damaged Spanish - $8.000
Foil Prices
Near Mint Foil - $31.700
Lightly Played Foil - $25.400
Moderately Played Foil - $22.200
Heavily Played Foil - $19.000
Damaged Foil - $15.900
Near Mint Foil Spanish - $31.700
Lightly Played Foil Spanish - $25.400
Moderately Played Foil Spanish - $22.200
Heavily Played Foil Spanish - $19.000
Damaged Foil Spanish - $15.900