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.
And yes, if you do commit to something like blogging, or writing and freelancing, you can and will make a living (you could even make way more than you could ever at your day job. That said, no matter how much time and effort you put into things like surveys, paid to click sites and things like that, they are not gonna replace your day job. They are just an attitudinal income generation options that you can use in your free time.
Really good article with some great tips. Affiliate marketing has the potential to earn lots of money and I'm hoping I can make it happen. I have tried the matched betting and it DEFINITELY works. The one thing I would say is that you need to check that any bets have been accepted by the bookmaker. I have had on occasion bets which look like they have been accepted but don't register in my account. Always go into your account and check outstanding bets or your bet history.