Hello Lights has a parabolic Mh
reflector on sale for $29.95 last time I looked at their site. I'm not sure about getting a MH
ballast at Lowes or HD
...you can get PC
ballasts there. If you want to do a DIY MH
ballast, look for an Advance ballast. You may have to come up with an enclosure. I'm thinking Bearfan or Timbo could probably guide you better than I can on that subject as they both have some experience with these type ballasts.
retro kits, AH Supply usually has the best deals and their products are very good. Or...you could get the parts separately. Endcaps should cost you less than $5 each. You can get reflectors for around $15-20. You can use a Fulham ballast or, depending on what size and how many bulbs, one of the Sylvania Quicktronics from Lowes. A Fulham Workhorse 7, capable of 220watts, should cost you less than $40.