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 mana value.
NM-Mint - $31.80
Lightly Played - $28.60
Moderately Played - $25.40
Heavily Played - $22.30
Damaged - $15.90
NM-Mint Non English - $31.80
Lightly Played Non English - $28.60
Moderately Played Non English - $25.40
Heavily Played Non English - $22.30
Damaged Non English - $15.90