(1) MBA ranking - check financial times ranking
(2) Business School Accreditation - There are lots of schools that are not accredit
(3) Focus of your MBA, i.e. marketing, HR ..etc
(4) Which school provide Distance Learning

Of course the higher the ranking of the school the more expensive it is

Check Bradford and Edinburg business schools they are not very expensive

"The best way to predict the future is to create it".