As long as you dont need radio, and are willing to settle for tethered/IR you can get a Super Empire Builder set for $310, otherwise the Zephr at 177 is going to be the least expensive way of entering DCC. I run the Empire Builder on my set, and it works well. I wanted something that was going to be a little more expandable than the Zephr, but I'll never be running more than 4 or so operators at a time.
I love my Digitrax Zephyr. But it is not the most user friendly unit on the market. Its advantage is its LocoNet backbone, far superior to the interconnecting methods of other brands.
That said however, if you're not a computer geek, many people find the NCE PowerCab or the Prodigy starter unit (I forget the name) easier to use. Another advantage of the PowerCab is that if your club uses NCE, then you can use your PowerCab as a cab at your club and an entire DCC system at home.
That is a respectable price for the unit, but I believe that without add-ons it only supports six locomotives running on your layout. Of course that's ample for many users.
The Digitrax Zephyr is considered the most powerful starter unit and the NCE Power Cab is considered the most user-friendly. I have heard people say that the Prodigy is comparable to the Power Cab in user-friendlyness. I've heard that Prodigy offers one unique feature not found on other systems, a "switcher" mode. By putting the throttle in switcher mode the throttle zero point moves to the center of the dial. then you can not only control speed but direction from the throttle, much like the old Bachmann brick-style power packs, going into reverse by dialing to the opposite side of the zero point. This is great for coupling and uncoupling. However, I don't know if the Prodigy Express has this feature, or it is only on the Advance2 units.