We generally use TCGPlayer.coms Market Price for most sealed product, though any specific price may be slightly lower or higher depending on a variety of factors
As for its card in Prismatic Evolutions, prices are going crazy at the moment
With Oathbreaker, I wanted to make sure that my first deck would be something that would speak to my sensibilities
I have both an understanding and an opinion on damage going on the stack, for instance, whereas when I bring it up in regard to cards that used to be much better under the old rules, like Yavimaya ElderYavimaya Elder and Sakura-Tribe ElderSakura-Tribe Elder, I usually end up explaining things for a good ten minutes
and if you do, Special Summon from the GY (only if they are there) the monsters used as materials for the summoning of the returned Synchro monster
Refer to the official event instructions and resources page if you are running a tournament Tournaments must be at least eight players to run, and unused promos should be returned to Ravensburger