When Phyrexian Devourer's power is 7 or greater, sacrifice it. Exile the top card of your library: Put X +1/+1 counters on Phyrexian Devourer, where X is the exiled card's converted mana cost.
Near Mint - $8.50
Lightly Played - $6.80
Moderately Played - $6.00
Heavily Played - $5.10
Damaged - $4.30
Near Mint Spanish - $8.50
Lightly Played Spanish - $6.80
Moderately Played Spanish - $6.00
Heavily Played Spanish - $5.10
Damaged Spanish - $4.30