Wow it's nice to hear about your wisdom in buying and selling of petrol. Its good that you can do there in Nigeria. In our country I think that is illegal. You must have a business permit before you can sell petrol.Over here in Nigeria, there is always fuel scarcity during Christmas especially from December 18th to 31th, and also January 1st to 13th.
I always buy off lots of petrol from filling stations and store them up. Once it's Christmas time when the scarcity kicks in, I resell the petrol three times of what I bought it.