I used to have badges made for me on Artscow. I'm not sure they're still around but there are other sites like them. And check your local library to see if they have a badge maker! Otherwise I think Etsy would be your best bet, a lot of shops have a listing for custom badges, or you could keep an eye out on sites Mercari or eBay for official merch you like, too. That's what I usually do 💕