Does Abundance apply to my opponent's sites as well?
Yes, they will get the benefit as well, if your Abundance affects their sites!
When do I get this extra mana?
Mana is added to a player's mana pool during their Start Phase, or when a site enters the realm under their control. So, any sites already in play won't get the extra mana until the start of your next turn. But, if you play Abundance and then play a site into Abundance's area of effect, the newly played site will generate extra mana immediately. Also, if start your turn with a in , and then during your the is no longer in (e.g. moving away, , etc.), don't the that gained during your .
Market
$0.89
Low
$0.50
Median
$0.95