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 - $11,900
Lightly Played - $9,500
Moderately Played - $8,300
Heavily Played - $7,100
Damaged - $6,000
Near Mint Spanish - $11,900
Lightly Played Spanish - $9,500
Moderately Played Spanish - $8,300
Heavily Played Spanish - $7,100
Damaged Spanish - $6,000
Foil Prices
Near Mint Foil - $46,600
Lightly Played Foil - $37,300
Moderately Played Foil - $32,600
Heavily Played Foil - $28,000
Damaged Foil - $23,300
Near Mint Foil Spanish - $46,600
Lightly Played Foil Spanish - $37,300
Moderately Played Foil Spanish - $32,600
Heavily Played Foil Spanish - $28,000
Damaged Foil Spanish - $23,300