What price would you put on a new barrier product for slugs and snails?

I am in the process of designing a product that will prevent slugs and snails from damaging plants and am trying to set a price point for it. My husband thinks that £11.95 per barrier would be about right, but I`m not so sure. May I ask how much you would be prepared to pay for such a product and would you buy one. It should last many years and can be used in soil or on solid bases