The ONE•1 - atm machine INSIDE the Migracion building on the Costa Rica side at Peñas Blancas (as you're exiting Costa Rica) WAS working when I crossed on September 11, 2014 - BUT - I heard that is NOT always the case so do it BEFORE you go (details on where below).
From my understanding of it, you need an
ATM CARD (NOT a Credit Card!!) HAS INTERNATIONAL ACCESS!!!(SOON I'll get some more details on the atm usage/fees but make sure you've informed your ATM card company that you'll be doing this in Costa Rica if they don't have that in your records)
I KNOW for SURE you can purchase your tickets at the MAIN BUS DEPOTS (San Jose and Managua) for $7 PLUS a $2 Convenience•Service Fee.
I'm not sure about the banks but SOME people were initially reporting having to pay anywhere from $1-$5+ ADDITIONALLY when doing it at the bank or a Travel Agency.
Just wanted to fill y'all in on what's up for NOW!