I saw my LYS selling blocking board for $90, it is too much for me. Then I found few websites that teach you how to make your own. So my hubby and I decide to make our own too.
We found a board from "Scrape Exchange", which is like a craft thrift store. The board is only $2, we believe that board is a panel for office cubicle. I took pics of the back, you can see the labels. And then we went to JoAnn to get the fabric, it costs about $3.50. So the total cost is less than $6. It is much better than paying $90.
I just used it to block my new cardigan. So far it works great.
The label on the back.