For my North Americans, I'm from Canada but I've lived in Europe... Lidl is like.. no frills/Food Basics. It's a deep discount grocery store/supermarket chain. Walmart, for example, inspires much more confidence than Lidl and would comparatively be more expensive. Does the US have Aldi? They're similar to Aldi. You want groceries for as cheap as possible, Lidl is the place to go.
It's just a very random place to sell a product for someone of her level of celebrity...