It sounds like you're a DIY guy and would be well served by a remote dealer here, like myself and Matt. Those prices are not out of line, but any homeowner can setup an Araknis network. No dealer is required if you have the equipment, but a dealer often ends up doing it because not many homeowners have the skills.
And yes Control4 has to have a stable, compatible network environment and Araknis is an excellent and safe choice, even more so now that SnapAV owns Control4. Control4 does not require its "own" or separate network. Rather your home network needs to be setup professionally with