Avacados happen to be one of the more expensive vegetables.. and the price is highly seasonal. You should see them for $0.8 to $1.2 "in season" and $1.5 to $2.5 "out of season". Perhaps an additional tax if you live in a big city.
if you want to talk about vegetable affordability, lets start with lettuce, carrots, and broccoli.
https://www.nytimes.com/2017/08/28/business/amazon-whole-foo...
https://imgur.com/a/6yozr