Well ... they're explicitly selling service for that price. The RedHat DB release includes RH 7.1 and PG 7.1.2 bundled together with one-point *support* for both via phone or web.
I have no idea how good that support is, but if it is good then it's well worth it for companies who want a supported database box. No need to attempt to diagnose a problem as being PG or Linux in order to figure out who to call, just call RedHat.
The appeal seems fairly obvious.
Of course you still have to figure out whether it's most likely a hardware or software problem you're having :)
