Redox has already priced themselves so high, it's unclear what value they are providing. A big reason to go with Redox is that you don't have to setup a VPN with the target hospital, have staff monitoring the VPN to ensure it's up and you don't have to parse your own HL7v2 messages.
IMHO Redox is now so expensive that you have to wonder if you might be better off doing all of this work yourself. As others have mentioned, there is a free Mirth offering and parsing HL7v2 is not that bad.