Contact MDA -
ALS Division. They have a "wish list" and will connect people who are selling wheelchair vans with those who want to buy. It is much less expensive than going to a dealer.
Also,
ALS Association sometimes has a "For Sale" section on their web site (ALSA Rocky Mountain Division hosts "Community Marketplace" on their website) where often you can find a good used van.
We are in the process of purchasing a used wheelchair van with ramp. Sadly, it became available when a friend of ours from the
ALS support group died. He had only had the van 9 months and had bought it from the widow of another PALS who died last December.
Take care,
Lisa