J.L.
You'd be better off giving her a Visa gift card. That way she can use it anyway she sees fit. If she needs it for bills, voila! She can use the gift card. If she wants to do something more frivolous she can use it for shopping, dinner out or anything like that.
I think they don't expire or have hidden fees either. So if she doesn't use it for a long time, it will retain its value.
DO NOT buy practical household items or groceries. She may need them, but...1. She may feel embarrassed or insulted and think you're trying to tell her something about how she runs her house and/or expenses 2. She may have particular tastes...even in household products and not like what you choose for her to run her home or eat.
If you're really bent on stuff like that, a store gift card for Target or a local grocery store would be more tactful and less embarrassing for her.