I MacGyver-ed a filter for my old camera (no way I'd risk the new one!) by putting two old-school blank cds together.
I don't think you can get them like this any more, without a brand label, just clear plastic. I put them shiny side to shiny side. The blue tinted plastic added extra filtering.
They were great for viewing the eclipse, in fact I wound up bringing down a couple of extra sets once a crowd gathered on the corner. A few people also had pinhole viewers, and they got passed around as well. An eclipse is a great way to meet folks!
As good as the cds were for viewing, they didn't really work well as camera filters, especially for an older, low-end camera. The sun itself is the bright glare, you can only see the eclipse as "lens artifacts" and reflections, sometimes multiple. Still, they're kind of cool in a way, and they're all I've got, so here they are:
And here is the shadow of a tree showing the arc pattern resulting from the eclipse.