Surprisingly I found few sites that offer a discussion of the pros and cons of leasing computers in school settings. Balancing the rapid depreciation of computer hardware against the life and cost of a lease for a single home computer. New Mexico State University went with a computer leasing program with Hewlett-Packard. This online link provides the details of that leasing agreement. By Malia Zimmerman.
Article uses examples to discuss the pros and cons of leasing for business and schools.
One big issue that these web links focus on is the fact that computer hardware depreciates very fast. Most of the leases are three-year leases for computer hardware. A computer will be pretty old, technology wise, in three years, and not worth much on resale. Some other issues that you can pick up on from these links, especially the University of New Mexico link, is that it is possible to set up the lease so that can buy equipment from several vendors, you can add new purchases to an existing lease, and you can renew the lease at the end of its term. I suspect that once you make the move into a lease, you will want to keep rolling it over and renewing it.