I understand that resources bought on a school computer and printed at school belong to school.
I buy and prepare a lot of things at home. I don't mind because it makes life easier and I like the style of a lot of the things I buy.
I share freely with colleagues at the same stage, or if it comes up in conversation- i.e. someone saying they're doing decimals and finding it tricky, I'd offer a particularly good resource.
It has been suggested we create a bank of resources and my name was mentioned as someone with a lot of resources. I'm mildly pissed off at being volunteered for it...