Can I share a shopping list with someone who isn't on RecipeFiler?

Yes. Open your Shopping List, tap Share and choose Create view-only link (or an edit link on a paid plan). Your phone's share sheet opens so you can send it by WhatsApp, text or email. The other person opens the link and sees that one list — no account and no app needed. If they can edit, they type their name once so everyone can see who ticked what. You can switch the link off any time.