The TSU6000 (ProntoPro) with the RF extender is probably the cheapest option. I have had mixed results with the RF extender, however, and have found that the Niles Intellicontrol and Crestron's touchpanels to be far more reliable. Pronto's RF extender operates on a crowded frequency range, and is more vulnerable to interference. House constuction (walls, concrete, rebar) also plays a role in determining the range of any RF system.