To avoid overpaying or purchasing counterfeit cards, stick to reputable sources
As for this deck's commander, popular choices include similarly controlling leaders like the Grand Arbiter or more aggressive creatures that seek to put beleaguered opponents out of their misery quickly, like Harbin, Vanguard AviatorHarbin, Vanguard Aviator, or Raffine, Scheming SeerRaffine, Scheming Seer
Once your treasures are in hand, you can continue playing value spells on the same turn, save them up to respond to a threat and/or make a bigger play later on, or hoard them so you can attack someone with an unexpectedly powerful creature
That means it might not net you that much mana and you might not have much to spend it on when it does, and, as mentioned, two mana is an enormous amount to hold up
Do you enjoy Commander
Low-cost characters (Captain Hook, Forceful Duelist and Goons, Maleficent's Underlings) can do much the same thing, running interference as you prepare