All the parts to make this should be available at your local hardware store. The only parts I had any trouble finding were the 3" pressure rated PVC and replacement valve stems, which cannot be had from the big box stores. You need a real hardware store for that. I don't remember exactly how much it cost me to put this together, but it was less than $50.
As with all projects on Instructables I've read that involve fire and pressurized air, I'll take a moment to say that I'm not responsible for your safety. However, I was able to put this together in one day and start making fireballs without any damage to life, limb, or property. If you're careful and at least cognizant of your surroundings, you really should have no problem with this.
That said, here's what you'll need to make the fire happen:
1 - 5 foot piece of 3" pressure-rated PVC (it's critical that this be pressure rated and not foam core)
1 - 10 foot piece of 1/2" PVC
1 - 2 foot piece of 1 1/2" PVC
1 - 3" PVC end cap
1 - 3" - 2" PVC reducing bushing
1 - 2" - 1 1/2" PVC reducing bushing
2 - 1 1/2" - 1/2' reducing bushings
1 - 1/2" pipe nipple
1 - 1/2" brass ball valve
2 - 1/2" PVC male adapters
1 - 1/2" PVC 90° elbow
1 - 1 1/2" PVC coupling
1 - replacement valve stem for a lawn mower tire
1 - can of PVC primer
1 - can of PVC cement
1 - roll of thread tape
An air compressor will be a huge help when you're ready to pressurize the device, and of course coffee creamer is a necessity. The final ingredient in this recipe is a few boxes of regular firework sparklers which are available everywhere. Even here in Georgia.