4wc,
I got mine from a paintball/dive shop (there's a perfect combo right there), and they set me up with a 90cc tank, 4500-3000 regulator with burst disks, and foster fill valve, for around $300. And that's in NYC, where everything is more expensive. If several were ordered in the same configuration as mine, the price would be less. I'll try to give you guys a picture later when I get home.
Tom Holland