Yeah, I always heard in my youth that McDonald's is the poor's restaurant (in the US at least). However it was never really the case e.g. in Hungary. It was always average priced at best. You can eat far better for far less in every moderate-sized town.
In the US you can get a burger and fries for $2 with their in-app promotions. On a per-calorie basis, it's actually very competitive with cooking yourself.