So, I found Classroom Collective. It had the best idea! Turn two metal filing cabinets sideways and cover with fabric to create a magnet board!
I didn't have 2 cabinets, but I used the one. The fabric was leftover from my bulletin board and the border was on clearance at Michael's for $1.
The border was peeling off in the picture, but here's what less than $2 made me :)