Comic boards are those white coated (acid free) hard cardboard like boards that are placed behind a comic book to keep it nice and straight. I did an internet search for comic book stores in my area and then called then for pricing. Do that because I found a $7 difference just in my city alone.
The cheapest I found them in my area was $13 for 100 boards.
The sign boards (coroplast) are more costly - cheapest I found was 50 cents each, which adds up. I loved the comic boards much better and they were much much thinner so they took up way less room than sign boards. Sign boards were fine for fabric which I had a lot of yardage of.
Also if you plan on laying any fabric on its side (which I did with home dec and flannel) you can just use the board as a guide to fold, and then slide it out for use with other material.
For the 1/2 yard fabrics I just cut the board in half - giving me 2 pieces.
Thanks again for the nice comments. Now I just like to go into the closet and "look", and am grateful for what I have, as well as my machines. Since I like to machine embroider I have a lot of other supplies which takes up room also.
Karen