I just checked out that site and they got a lousy selection of cheap lights and when I checked out the AN nutes I use their prices were about 20% higher than the hydro store in Edmonton where I've bought a lot of stuff the last 15 years. That free shipping ain't really free.
I was out in BC a month a go and scored a used magnetic 1000W MH/HPS ballast for $70 as my old 1000W MH one needs a very expensive, $225 Hortilux conversion bulb for flowering. Last year out there I got one for $170 and have done one grow with it so far. I'm still using a 16yo 400W EYE Hortilux conversion bulb that runs off an HPS ballast for MH light and the plants seem to grow fine under it.
I picked up a couple of Chinese Super HPS bulbs for $40 each. Light EnerG brand. Says on the box they work with magnetic or digital ballasts. Regular 49.95 but he gave me a deal as I was spending a thousand bux. Compared the spectral output pic against the Hortilux one at the store and they are near identical. I doubt they will work for 16 years but for flowering I'll want to replace the bulb every 6 grows anyway. As I only need 1 - 1000W for my grow I now have backups in case the only one I did have blows on me or that MH ballast fails.
Check out the size of that 1000W Hortilux conversion bulb compared to the standard sized 16 year old 400. Like a freakin' football and barely fit in my reflector. That's an 18" ruler too.