Couple questions

First, can anyone tell me where the best place to get the cheapest HPS 400 watt????

.........And second, how big of a box should I make it for 10 autos at a time. Being they stay short and small, I figured I could prob get away with 3x3x6ft?????

Try ebay thats where I got mine, it was really cheap but no name brand or anything. Height depends on how big your buckets are etc but 6ft seems like plenty, and if they seem like they might be too tall start some LST.

You get what you pay for with digital ballasts. Ive compared brands and the "cheap" ones produce up to 20% less lumens than a Lumatek or Quantum, but they do cost a bit more, ebay is the place to look. I did 10 autos in a 3x3x6 tent without any problems.

With my no name 400w I got 8 oz my first grow with bagseed, a little over .5 grams/watt. I'm not saying that it couldn't have been more with a name brand ballast but it got the job done for sure and is still getting the job done.

If you have the money go for the name brands but if not the no namers will get it done.

Thanks there somedude! I was thinking a 3x3. Just gonna do a simple 2x3 frame OSB plywood the outside, paint the interior flat white and start settin it up! Was gonna do the CFLs I bought 12 for flowering and 12 for veg, then I was thinkin maybe just a 400hps. Do 10 autos for a first grow, hopefully it goes well. I never have great luck with germination. Do you think those inline dryer vent fans is good enough to pull fresh air in through a charcoal filter, and one for the exhaust, they are 6 inch.