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 - $14.20
Lightly Played - $12.80
Moderately Played - $11.40
Heavily Played - $9.90
Damaged - $7.10
NM-Mint Non English - $14.20
Lightly Played Non English - $12.80
Moderately Played Non English - $11.40
Heavily Played Non English - $9.90
Damaged Non English - $7.10