Whenever Tyrannosaurus Rex attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.
NM-Mint - $17.60
Lightly Played - $16.80
Moderately Played - $15.90
Heavily Played - $14.10
Damaged - $11.50
NM-Mint Non English - $17.60
Lightly Played Non English - $16.80
Moderately Played Non English - $15.90
Heavily Played Non English - $14.10
Damaged Non English - $11.50