While it's not a requirement to play the game casually with your friends, if you have valuable cards, or if you're playing in a tournament, you absolutely need to have them
Do you sort by type, color, or set
A heavily played copy of Squandered Resources will now set you back $59.98, not even including shipping
A 3/4 human samurai for three mana, Isshin states that if a creature attacking causes an ability of a permanent under its owner's control to trigger, that ability triggers an additional time
Scalpers are continually a big problem, especially for those going through the Prismatic Evolutions deck sets and trying to get ahold of those card sets
That's very strong, and you can easily build around it as a way to make a free dork without jumping through any mana or cards or tapping or "once per turn" or anything else