I bought my Heaton 10 stuff separately and saved quite a bit of cash. As for the 585, it's the same pad as the 590, so you can probably find online reviews for the 590.
Only place online that I know sells the 585 is Goalie Monkey (located in Anaheim, California):
585 Pads ($1,000):
http://www.goaliemonkey.com/koho585-pads-sr.html
580 Blocker ($200):
http://www.goaliemonkey.com/koh580prosrg1.html
580 Catcher ($300):
http://www.goaliemonkey.com/koh580prosrg.html
I personally think $1,500 is a little overkill unless you're playing at a high level. But to answer your question, the bulk deal on eBay looks like it'll be a $100-$200 cheaper than ordering online. Although you're stuck with 33" pads and that color scheme.
If you're just playing in a rec league, I'd suggest checking out the Itech 7.8 or Heaton Z pads. They're in the $500 range, and they have most of the amenities that the more expensive pro pads have.