Worth looking in to. I'd try to get him down to no more than $6,000 for both the van and machine. Be sure to inspect it in person and even better take it into a truckmount mechanic and have it inspected.
If you do buy it just realize you are buying an old van with an old machine so it will be important to keep $3000 in savings for repairs. $3,000 is enough to fix just about any catastrophic failure you may run into.