Dude, 1 hour is not nearly long enough for waiting for a response.
AFAICT, You Mail is free - but if you use it, then obviously you're probably going to use airtime if it actually dials out to the You Mail servers. Conversely, if you listen to the recorded message without dialing in, you're using DATA.
The service itself is pretty good, it has advantages and disadvantages over the built in Google Voice.