Like the photos suggest, a wide, flat, clear area (about the size of two parking spaces) is needed so the tires can be worked on
The vans carry the Hunter mounting/breakdown machine to get the old tires off and install the new tires on the rim, plus tires, plus a Hunter balancer, and a compressor to get them inflated.
Tire price comparison, as that is half of what it takes to get my business, the price for the least expensive 215 60/15 is $85 plus costs of $30a tire ($25 per tire for installation, 5 for TPMS). That would be $230 total cost.
My go-to tire shop, Discount Tire has their low cost tires at $250 out the door, road hazard warranty included. I compared prices in 2007 at 6 tire shops around San Diego, and Discount Tire was the least expensive, and best service too: http://choosingscars.blogspot.com/2007/04/how-much-for-pair-of-tires-heres-what-i.html
Right now they carry 85 brands and models available in my example size, so you have options in prices and brands, I go for the least expensive when buying for my daily commuter.