DCC is an initial investment of less than $100 to several hundred for a "controller" that usually includes a power supply, a command station and a throttle.
Then you will need to add a decoder for each loco you want to run. Depending on features you choose (number of lights and functions, sound, etc) this can be anywhere from about $20 or less to $100+ each.
You should also consider that if you want to have more than one loco running at a time, controlled by different people, you might want to have additional throttles. These also range form under $100 to a couple of hundred each.
I will use what I have so you can see how one person got started, but if you do a search, you will find that many different people have started with different combinations, and have also been happy with their setups.
I have a Digitrax Zephyr. This is Digitrax's "entry level" system that looks and operates much like a traditional DC powerpack. It has a forward/reverse knob, as well as a large speed knob that goes from "stop" to 100, just like a DC controller.
The Zephyr has enough power to run 4 or 5 locos simultaneously, which sounds like more than enough for your setup.
It has the added advantage that you can hook up DC powerpacks as additional throttles (up to two) negating the (immediate) need to purchase additional throttles. However, I have a UT-4R, which is a handheld radio throttle, for use at the club. They use the same system, and have radio receivers.
The current price of the Zephyr is well under $200. Common, basic decoders can be had for less than $20, so you are looking at a relatively small investment. It may be comparable to what you were thinking of spending to set up a 2-cab DC system.
Andrew