I found this Omnigrid mat for $3.49. I hadn't known about them before, but they are a nifty little thing. Half of it is an ironing pad (right side), and the other half is a grid/cutting board.
It is very sturdy and heavy. And bonus, it folds up for storage!
I've already used it a couple of times, and it works great! I couldn't find the exact size online, but a slightly smaller one sells for $25 on Amazon!