@elizabeth I tried the same refrig magnets and yes they do work, maybe not to the effect the ones selling for $600 do (but don't know since I've not compared) but others should try this tweek out and let all know their experience.
https://www.amazon.com/Magnetic-Erase-Whiteboard-Sheet-Fridge/dp/B07CJNTW6D/ref=sr_1_9?keywords=roll...
https://www.amazon.com/Magnetic-Erase-Whiteboard-Sheet-Fridge/dp/B07CJNTW6D/ref=sr_1_9?keywords=roll...