There is an Open Source Solution available, Open ERP and OTB Africa is the only partner in East Africa that can help your organisation in customizations and implementation strategy for the solution and the full ERP if need be. check this link for more info https://www.openerp.com/partners/directory 
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kind regards,
kibe wachira.
software developer.
tel:+254721888474
email:kiffea@gmail.com