That's what really astonishes me. It really ain't cheap. You can get a much better quality pub meal for virtually half the price. I've heard some people try to claim that dissing MacDonalds is snobbery, and that "it's the only place some people can afford to eat out". Bollocks is it. On the contrary - even if we wanted to my OH and I can't really afford to eat at the local MacDonalds, but we can share some tapas at the lounge bar type place two doors down for a fiver each including a pint.
It was the same thing with one of Jamie Oliver's crusades. There were stacks of people claiming that they "couldn't afford" to feed their kids healthy food, and that's why they had to give them doner kebab takeaways for dinner. The meals were about 7-8 quid each IIRC. Jacket potato with beans or tuna, and some cherry tomatoes - about £2?
There are plenty of valid points around the issue to do with education and awareness, the confidence/skills needed to cook at home, and so on. But the affordability aspect is patent bollocks. Healthy eating doesn't have to mean organic goji berry risotto.