The selection almost always includes a mixture of brand new cards (where the card name, in-game rules, and art are all new) and 'reprints' (new versions of existing popular cards, which keep the same name and rules, but may feature new artwork and sometimes updated wording)
Cathars Crusade Although its always being reprinted in Commander supplemental sets, Cathars' Crusade never gets cheaper
Tron has some vulnerability to discard and counterspells, but Valakut cannot be Thoughtseized or countered
the answer, barring a spectacular add-on, is oneor even zeromana
If that sounds convoluted, please spare a thought for those of us who write or edit for a living and now have to do work while playing Magic: The Gathering
Wed have to be playing a pretty extreme flash matters deck, as Springjaw Traps rate is much worse than we have commonly available