'Free food' refers to the Slimming World Diet - it means it's free to eat, won't cost you any dieting points. There's free foods and pointed foods. The meals are £3 each.
The slimming world meals are a real hit or miss. I had the Chinese style curry and the chicken was almost rubbery The diet cola chicken was lovely but had a severe lacking of chicken. The beef lasagne is smashing though.
It's not me. I've used the Iceland logo pic but the mod have changed it. It is annoying and frustrating that sometimes those change that the mod made do more harm than good on the deal.
So that image of the box you've used says "Free Food". How is it $9?