[onetwothreefour]

The nominal cost (cost to the bank) is here:

http://www.frbservices.org/servicefees/fedwire_funds_service...

It costs less than $1 to send a FedWire. The FedWire can be up to $1BN. :)

The FedWire system is actually very similar to transfer systems in other countries. I'm not sure why ACH is still in use apart from as a way to digitize checks.

That said, most banks charge, at minimum, $12 per wire in/out for personal accounts. Most business/corporate accounts get wires free since that's how people pay each other (something like $1TN in wires is processed every day).