It's always good to be wary when purchasing rare cards especially when they can be sold for hundreds, if not thousands, of dollars.
Sacrifice after III.) I, II Target player mills two cards, then exiles their graveyard
However, a significant portion of their business is also dedicated to Trading Card Games (TCG)
(11/8/2024) "Flashback [cost]" means "You may cast this card from your graveyard by paying [cost] rather than paying its mana cost" and "If the flashback cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack." (11/8/2024) You must still follow any timing restrictions and permissions, including those based on the card's type
This is good in certain situations where you have a Pokemon that needs a little energy boost in a pinch
It's a format built for epic plays and social fun