Craigslist that shit. I don't know where you're located but CAP regs go for between 50-100 here in socal. I've also seen 20lb aluminum tank/reg combos for 75-150. Amazon and Ebay aren't the only places on the internet.
Don't know if anyone answered this for you or not but don't cut the cords on the ballasts. You would need to get a adapter cord for it.
http://www.amazon.com/Hydrofarm-Lamp-Cord-Adapter-System/dp/tech-data/B00286QOL8
They also have the ones that switch it the other way from Sun System to...