Buying and selling real products is one sure way to make money in Nigeria.
There are two options to consider. You can choose to be a retailer or sell your own products.
You need some capital, but this is not always the case.
Get a product that is in demand in your locality and sell to them.
People are spending much on electronics this days, so consider this. The good thing is that you dont need a physical store/shop. Open a virtual store on Konga or Jumia Nigeria and start making your money. Best of luck.