Years ago I found a great source for magnets. I really do not know where
it came from... some craft catalog. It is an enormous coil of an
adhesive backed magnetic strip. The strip is one inch wide and... I
guess I bought 25 feet or some insane amount. (very heavy!) I cut it
into 1" by 1" squares as needed and use them for everything. Just leave
the covering on the adhesive side and reuse them over and over. I just
looked at my chalkboard and counted about 40 of them in use at the
moment holding up posters, original art, map of the world, and quotes.
Think I bought it originally for magnetic backing for a project students
were making that was used as a refrigerator magnet.