Currently it's at about 77 US cents per average transaction, with the fee paid by the sender. A month ago it was briefly above $2.70.

VISA transactions, with the fee paid by the receiver, obviously pull more off the top in excess of electricity costs (for larger transactions), but they also have purchase protection, customer service, and things such as points built it for particular cards. So not a complete apples-to-apples comparison.

That's only first layer transactions. Second layer transactions are orders of magnitude cheaper. Think of layer 1 as your checking account and layer 2 as your credit card. You don't use your checking account often.