There be 25 square feet per box for those missing fingers and toes.
24.99 on Amazon.
Sivan MAT-LOCK-BLK Interlocking Foam Puzzle Exercise Mat, Black https://www.amazon.com/dp/B00U0HJCB6/ref=cm_sw_r_cp_api_yd5-ybD9QGP7P
Improve your internet search terms. Or, see updated link above.
LOL. Not the same product.
We’re selling this product. It is made of rubber.
You’re linking this product. It is made from high density EVA foam.
I won’t make a snarky retort. 
Erm, this Woot says “Made out of high density soft rubber”, not EVA foam.
However, this different (and even cheaper!) Woot says “Made from Premium non-toxic durable EVA Foam”:
Yeah, I got them backwards. Fixed.
Regardless, the item linked as a price comp is not the same item.