I think you can buy them at RadioShack. You purchase the system for $149 (1-room) or $199 (2-room) and get a monthly credit on your bill. I think it is like $10 a month discount until the system is essentially free once all the credits are factored in. You can install it yourself, but I believe that installation is included with that system through DNS. Check with RadioShack to see if they still offer it.
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