Omniscience

[average_j03]

Could I pay buyback, overload, or X costs when  {Omniscience} is on the field?

[Keyeto]

It would be just like any other situation for casting cards without paying their mana costs, so...
Buyback: Yes.
Overload: No.
X costs: X would = 0.

[blckjckjimmy]

The card says may. What if I choose to pay the CMC. Could I then overload, entwine, etc. The player has a choice/opt.

[Birdbrain]

So then you could slap a replicate card on an {isocron septor} and replicate? Because it says "may" in the text...that is of you pay the casting cost of the imprinted card?