WinifredNworah To be very honest. N20k can't even start you any business that is sustainable in Nigeria. No matter how little. If you make it somehow and your business grows, then its either you are a business mogul or God is working out something in your life.
Firewood, Frypan, G.Nut Oil, kerosene, Beans, Mortar and all ingredients needed to start akara business is worth more than N20K today. Where is the contingency money incase things go bad. I really don't know how to advice you on this.
The only thing I can say is that for N20k, I'll suggest going into non-perishable items. Things that have longer shelve live incase you don't sell off on time. The item of choice is entirely up to you to decide.