When I started out to do my own Christmas lighting, I looked at the available controllers, and I knew I could do my own for less and have lots of room for growth. This is why I built the 32 universe controller. It has about $80 worth of parts and has plenty of options for growth as I expand my lighting display. In addition, I can add a display element on a single control line and not worry about wasting channels, since I have many universes and the cost is low. The outputs from the controller are run through a RS-485 buffer to each group of the lights, so on the receiving end, there is a receiving circuit card.
One Large Controller
Even though I only have buffers from the controller to the lights, these still cost around $5-$7 a universe for the buffering. The pixel output of the controllers can be run 10-15 feet, so if you can group your lights around a controller, you can reduce costs some more, since no buffers are required. So, any time you have a connector, buffer, switch, change format of the data, it costs you money. So the lowest cost solution would be a few local controllers as shown below.
This is true for both the RGB full color lighting as well as for the AC (wall plug) power for incandescent lights.