Then exile it.) "Flashback [cost]" means "You may cast this card from your graveyard if the resulting spell is an instant or sorcery spell 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." You must still follow any timing restrictions and permissions, including those based on the card's type
Some move because they are attached to a famous final evolution
You can look at the top card of your library and cast them anytime by also sacking a nonland permanent, plus their costs too
It is limited to the copies still on hand and is not being reprinted, so once it sells out it is gone for good
The default of when the if condition is not met is to put the card back on top of your library, this gives the ability modality, and is not what made it a triggered ability
Coveted Jewel's last ability resolves after blockers are chosen but before combat damage is dealt