If you can't find the Black Mat used in the video, try searching for a "Steady Betty" pressing surface. They come in different sizes, 12" square, 16" square, 12x16", etc. The smallest one starts at about $32 and prices go up from there. However, the best deal I found was buying the small ironing board cover kit which is 14x60" for about $27. Four friends could get that, and cut into 14x15" pieces for a fraction of the cost. The Steady Betty holds the fabric when I iron so there is no stretching - sometimes I forget to "Press" and instead move my iron around, so this helps to keep my fabric blocks from becoming distorted.
There are lots of options for the Steady Betty available on ebay or Amazon and some quilting suppliers carry it, too.