Fork

If you copy a spell for which Buyback has been paid, you get nothing back since the copied spell does not have a card to give you.

You need not (and may not) pay any additional mana or other costs (like sacrifices) to use the spell which is Forked. You get control over a complete copy but can change nothing except the targets.

It does copy the mana symbols in the mana cost for the card it is copying, but it uses its own color definition and not the one from those mana symbols. This is so it maintains its color just like the text says.