I was thinking of getting 2 or 3 of these for my plants, hopefully I'll get a discount for ordering more than one, I've asked what bulb types are in there,what do we reckon

Commercial Metal Halide high bay 400w light with lamp - eBay Lighting, Building Materials, Hardware, Construction, Business, Industrial. (end time 05-Jan-08 15:37:53 AEDST)

Would they be your main growing lights, or do you just want something to use during the vegging period?

If you're just starting a grow room, then you'd be better off going for a regular HPS + reflector setup. You can get one with a digital ballast which works with both MH and HPS bulbs, so you can still use MH for vegging, then switch to HPS for flowering.

The lamp you're looking at probably won't work with HPS bulbs, and MH isn't very good for flowering (wrong spectrum) Also, they are 'used' so the bulbs may be past their best. I would never buy 'used' bulbs, since they only last about 9 months anyway, and the output diminishes over time.