I don't know exactly where you are, but if you have access check out habitat for humanity. I have seen nice lights in there for cheap among other items. Maybe consider checking pawn shops as well or craigslist. Btw thank you for your service to our country.
600 watt HPS is more efficient than T-5 as well so your power consumption will be less for the same amount of lumens (100,000 for a 600W HPS)for a T-5.