Originally Posted by humancarpenter
Make one with 2" PVC, a Sprinkler valve, and a 12 gram CO2 adapter. There are plans on the internet. You could probably do it for under $50.
Most commercial fields will not let you use homebrew launchers made from PVC these days. They are too unreliable and if one explodes while aired up it turns into a very bad day, very quickly.
The metadyne is a great option!