Cyber cafe in athi river - hmm lets see ...

You must have a good population of young english reading and english speaking people.. preferably hi-skul and college students..
Without that, it shall not pick.
Studies have shown its these that drive use of IT solutions.

10 computers is a good start up - but if there is no physical connection to the packet backbone, you will pay dearly for satellite uplinks / downlinks.
If there are landlines [data capable] - the best option is Orange/Telkom as an ISP.