They have "conversion kit" ballasts now available for about $100-$150, and then including the Phillips lamp for $80, you could probably get setup with a 315 w CMH ballast, the lamp, and a reflector for $220.
The nanolux is usually $250 for the relfector/ballast alone, with no lamp.
I've been researching the 315 W CMH options for a few months now and by far the cheapest options are your "conversion kits" that come with a little converter that allows you to plug the lamp into any E39 base, and a ballast, much like any MH/HPS setup would come with. You can even find these kits with the Phillips bulb included for $200, and so then you're basically left to however much you want to pay for a reflector.
A note on the Phillips bulbs though, be careful if you get the 4100 K spectrum. This one pumps out a lot of UV light and can be an extreme risk if the "envelope" (the glass" on the bulb breaks and will essentially give you an instant tan and a bad case of welder's eye. So if you're going to run the 4100 K, get some kind of hood with glass at least. The nice thing about the SunSystem LECs is they come with a little glass cover for this--a lot of owners of these don't run it because they don't want to lose the PAR, so you might be able to buy one second hand.
tl;dr hop on eBay and search "315 w cmh conversion kit", then buy an E39 base reflector/hood to go with it, and you just saved $200 on your first CMH