Right now at Walmart, you can get this Pen + Gear 8.5×11 magnetic dry-erase board for $3.30. This is the best deal from a reputable source!
This dry erase board set includes the board, a dry erase marker and a clip. The magnetic backing allows it to be placed vertically or horizontally on any magnetic surface.
Walmart offers free shipping for Walmart+ members or on orders of $35 or over.