Hi there,
The cost of living in Tanzania is about the same as in any first world country if you wish to maintain the same standard.
Schools vary greatly in quality and price. The International School of Tanganyika is good quality but at USD5000 and up per trimester, it is the MOST expensive. The French School is much more reasonable at about USD900 per trimester. Classes conducted in French. Haven Of Peace, supposed to be a good school (it was not an option for me as it is geared toward missionaries and their children first, then others), religion and the teachers are volunteer and far from where you would most likely be living. Dar es Salaam Independent is apparently the best value for quality. Not familiar with fees.
websites for reference:
http://dsmindependent.tripod.com/
http://www.istafrica.com/
email French School for info, they are helpful.
frenchschool-tz@africaonline.co.tz
and an expat info site
http://talesmag.com/rprweb/the_rprs/africa/tanzania.shtml
Hope this helps. Email or post here for ?s or more info.
Cheers,
Patricia