Ob Nixilis, Captive Kingpin It takes very little to break Ob Nixilis, Captive Kingpin

Sort Card Type Duosion #56Uncommon $0.53 Duosion #51Uncommon $0.54 Duosion #43Uncommon $0.33 Duosion #75Uncommon $0.46 Duosion #34Uncommon $0.22 Duosion #77Uncommon $0.09 Duosion #71Common $0.11 Duosion #38Common $0.13 Duosion #31Common $0.13 Duosion #41Common $0.13 Duosion #31Common $1.99 Duosion - 041/086 #41Common $0.11 Duosion - 041/086 (Master Ball Pattern) #41Common $3.76 Duosion - 041/086 (Poke Ball Pattern) #41Common $0.39 Duosion - 119/086 #119Illustration Rare $16.32 Duosion - 124/086 #124Art Rare $9.79 Duosion - 2011 (Ross Cawthon) #56Uncommon $0.68 Duosion (Master Ball Pattern) #38Common $16.05 Duosion (Poke Ball Pattern) #38Common $0.53 Duosion - 119/086 #119Illustration Rare $16.32 Duosion (Master Ball Pattern) #38Common $16.05 Duosion - 124/086 #124Art Rare $9.79 Duosion - 041/086 (Master Ball Pattern) #41Common $3.76 Duosion #31Common $1.99 Duosion - 2011 (Ross Cawthon) #56Uncommon $0.68 Duosion #51Uncommon $0.54 Duosion #56Uncommon $0.53 Duosion (Poke Ball Pattern) #38Common $0.53 Duosion #75Uncommon $0.46

But you get to cast the real one later for free, so the best pattern is to play a cheap spell first and a bigger one later, like a Time Warp or Stock Up
Currently selling for an average of around $69 , Perrins card is another which has an Uncommon variant that costs much less
2/132 Blaine's Charizard(Holofoil)
Its an ignition effect, so it wont be used most of the time, but its very nice to have whenever it comes up