You need minimum four swamps in play before this starts netting mana, but the mana advantage gets better and better with every land you play
While the initial impact of this card isn't as huge as say, Wrenn's Resolve, Phyrexian Arena can stick around and benefit you for the entire game
It can be very strong in some matchups and very bad in others, so think a lot about it during sideboarding when you decide to keep or not this card in your deck
Create a token thats a copy of that card, except its a 3/3 black Zombie creature in addition to its other types. This means, if the circumstances are right, you can get lots of your enchantments back for free
Alot of promo cards have no current listings, so TCG Player and other sites have no market data
In Modern however, the monkey is less problematic, since there is no Force of Will or Daze to protect him through the early turns