Good job OP, I have notice one thing within the locals and you just brought it to my attention. Whenever there is a new tech that involves money, the smart and educated ones usually take advantage of it from others(the scammers do refer it to as
update), glad that you are informing and educating the locals around you so they don't fall victims of these guys. I think what contributed to these Ponzi schemes is the inadequate direction of finance and exposure, people love means to get quick money and that is exactly what scammers use as a fishing net to farm their money.
ANSWER: You can buy bitcoin of any amount but some p2p recommends a minimum of $10 which is around #7,000
We also have p2p usually refers to as merchants, some of them have vendors, you can contact them like we do have some in the forum from the Naija board and you may be able to buy as low as that and they have a reputation here as well, it is better you contact them physically, that way nobody can run away with your money. I know a guy I do sell to times and meet sometimes when it involves large transactions because I dislike using centralized exchanges since I did more research about them.