This is true even if you somehow no longer control a commander as you finish casting the spell
You can do some interesting things using effects like Sword of Hearth and Home and Bazaar Trader, the latter of which can give you a treasure for passing on something you already borrowed, and making sure it never goes back
Mickeys the most expensive card on this list by some distance, and will set you back $1,022
If, during a player's declare attackers step, a creature that player controls that's been goaded is tapped, is affected by a spell or ability that says it can't attack, or hasn't been under that player's control continuously since the turn began (and doesn't have haste), then it doesn't attack
Value : If the deck includes cards that have higher individual value or are highly playable in many decks, the higher its rank