Since you haven't bought yet, try to find a gun with a minimum of 2 mags. Used magazines for this model on eBay are fetching $150+ a piece, but sellers will often throw in their magazines as a package deal and save you some cash. These magazines, like the gun, are discontinued and there are no 3rd party mags available.
The gun itself may or may not be finicky on the amount and type of powder used. IIRC, it was designed to use Bullseye, but several members have used other fast burning powders with success. I seemed to have gotten one of the finicky ones.