Dayo, sadly, because of the market size, app related business remain only profitable in a few western countries. I don’t know of any that could be used in Nigeria. That said, you can always put your own twist on things and make something that people in your local area could find useful. Essentially, you create a niche market out of it, and that can be very profitable.
The best part about being a YouTube Partner is that it’s free to join (although there are a few requirements but more on that later) and once you become a Partner and enable ads, you don’t have to do a single thing. Google Adsense will take care of everything for you. All you need to do is create quality videos and promote them so you can get more views.
If you do pretty well with capturing leads for an affiliate or CPA network like Peerfly, you might want to consider building your own email list of leads. MailChimp is popular email list-building service that lets you gather up to 2,000 email subscribers for free. You can also create and schedule emails to be sent out to your subscribers, which you can use to send them purchase links to affiliate products or even your own products that they may be interested in buying.
Make money fast either online of offline is a subject that is near and dear to my heart. I can remember from my childhood days having a coconut stand in the US territory of Guam – Imagine that a 6 year old Entrepreneur selling coconuts from a stand. Forget that you can go in any yard on the island and pick up your own coconut, but who could resist a 6 year old business mind.