In my country, It is quite above $1 to get a decent plate of food that will satisfy your appetite. It also depend on the type of food you actually want to eat at a time, if you will like a plate of food , which goes for about $2 and that will not satisfy you especially if it a pounded yam, Semovita ,Garri or others, it means you have to get about 2 to 3 plates more to be able to be satisfy your hunger, probably about say $6 to $8 will actually take care of your lunch.And if you are the type that likes extra meat, fish, Chicken ...etc then actually your spending may be close to $10  that is with drinks and others not mention.
Most of the time many people try to cut cost to avoid spending so much so as to be able to meet up with the payment of so many other bills, and that make a lot of people to  prefer  buying  food stuff and prepare it by themselves as this has been seen by experience men and women who have tried buying food from food vendor and cooking such similar food at home , and have come up with the idea that  cooking at home is a means of saving cost, so as to be able to  meet up with other needs and challenges .