Apple leases iBooks for £7.58 a week to UK students with an option to buy for £50 afterwards. The lease program is called iStudent. Students can lease for 1, 2, or 3 year periods with an option to buy. I don't see this offer for other countries, too bad.
Peter
http://www.apple.com/uk/education/istudent/
Peter
http://www.apple.com/uk/education/istudent/