Not sure where you're located but you can easily find them at most big box retailers. (Walmart, Lowes, etc) but you can definitely find them on Amazon as well. Nor sure if links are allowed but if they are here is a link for you!

https://www.amazon.com/Mr-Clean-Original-Cleaning-Durafoam/dp/B07M6R4LPN/ref=mp_s_a_1_5?keywords=magic+eraser&qid=1570313519&sprefix=magic+e&sr=8-5