There are many strategies to use, and since there are over 10,000 different cards, and more to be added in the future, there are plenty of ways to make any kind of Deck to suit players' individual preferences
Once a buyer realizes they bought a fake card, it might be too late to recover funds, especially if the seller is unresponsive or disappears
Buy 6 - Get a Sealed Case
While it may be tempting to shotgun the floodgate reborn early, its far better to leave your opponent guessing, and potentially use the second to try again if, say, Radiant Typhoon MSTs the first
Though, if you happen to have Gyarados ex and Vaporeon built and lets say your Articunos HP is running low switch in Gyarados using the Leaf Supporter card or some X Speed Item cards