AIBU?
I don't think the householder should have to pay.
They cost a small fortune, 4-ish pounds for 5.
They are soon used up with a family of 5, it must be worse for larger families.
I think they should be provided by our council.
This week, nowhere in the area even stocked them so we had to use plastic.
Guess whose rubbish was left sulking in the bin? 
I'm serious though. They are not widely available and they are very, very expensive!