We went to Daiso in Redmond today to get some last minute fun stuff for our niece. If you’re not familiar, Daiso is a Japanese dollar store (well, $1.50 store )
I always check the the office supply and craft sections for tools and materials and today I found four-packs of 13mm x 2mm neodymium magnets and two-packs of 12" bar magnets in easy to grab angled plastic holders – each for $1.50 of course. I just picked up some similar neodymium magnets yesterday for $5 for 2
The bar magnets are not super-strong but hold down thin materials easily and they keep a consistent pressure across the entire surface, not just in spots where the magnets are.
Here are the bar magnets holding down a sheet of felt:
They also had 12" x 18" (or so) x 3mm flat sheets of “100% natural” cork, as well as 6mm in smaller sizes, for – you guessed it – $1.50. If you have a Daiso nearby be sure to check them out for supplies!