Monopoly is a market structure where a single entity controls supply, pricing, or access of a particular commodity. Some sections in Nigeria has suffer a hike in price of it item due to the monopoly nature of the item. This in one way or the other has contributed to the cause of inflation within the country. With monopoly, few selected individual are enriched leaving the rest in poverty.

Below are examples of monopoly that has affected citizen within the country either directly or indirectly:
Telecommunications: MTN was the first and only network in Nigeria at the early 2000s. Then, just buying their sim cost very high. After some years, other network like Glo, Airtel and others came. This bring a competitive market into the telecommunition system and made the price of everything in the telecommunication system come down to the extent that almost everybody (including the kids) in the country can avoid it.
Dangote cement: Dangote is the largest manufacturer of cement in Nigeria and this has made it easy for him to control over the market prices. Increasing the prices at his own convenient.
Digital Satellite Television Nigeria (DStv): This is another monopoly firrm that controls the pay-TV market. They had no competitor and this made it easy for them to increase subscription rate without any justification.
Dangote petrol: Dangote was believed to has come into the petroleum section to help stop the monopoly of petrol brought by NNPC before the existence of Dangote's refinery. But seems Nigeria Petroleum section is still under monopoly as petrol price is now majorly controlled by Dangote.
CONCLUSION:
Monopoly may be good in business for the businessman, but it is disastrous when it comes to politics and governance. It add to the struggles of the citizen as price of such items is been controlled by an individual leading to increase in price without any justification. Imagine what will become of DSTV if we have like 5 more firm that run similar service.