You simply choose whether or not to pay that amount of as the ability resolves
As for the Friends & Foes lineup, it is priced at $40 USD for the non-foil and $50 USD for the rainbow foils
You also dont have to blow up one of your own lands (though you can if like)
Now, theres another reason to be excited about holofoil cards
This deck also runs a handful of Pack Rat-like creatures that check the number of rats you control to determine their power, toughness, or both
It's just a large blobby looking thing, but with creepy eyes, a semi-humanoid shape, and a mouth that's clearly meant to come off like a skull, it's a standout amidst a set of great art because of how downright horrific it looks