I once started a maize business. Actually, last year. It is a good business venture because demand is always there and supply is limited many a times. This is a crystal clear fact that you are always assured of the market.
So, get an assured supplier. It’s best if you went to the farmers directly. Use an expert to get the best maize with least moisture content (buyers will always measure that) Once you have supplies, get into the market. Here, go for millers and direct consumers like schools, NGOs, domestics online (used to get most of my customers from OLX). At all costs, avoid brokers because you will get conned. Sell at a profit and repeat the cycle.
But remember that like several other agribusinesses that have great potentials for both scale and profitability, starting a maize selling business in Kenya is a great venture to start up if executed at the right scale of a constant supply. This will ensure you produce a substantial volume that can be sold profitably, both locally and for exports. You can source for a supply from places like Kitale in Trans Nzoia county and some parts of Uasin Gishu county.
It is a risky business, so I strongly recommend you to start small.