$20 is the FULL PRICE pillow case (the stuffing inside is NOT INCLUDED as this will vastly increase shipping cost). This will be a 35X35cm pillow, two sided (same image on both sides). The material is a mix of cotton and polyester nicknamed "peach skin".
We recommend you use a 50X50 insert (we used the one from IKEA): http://www.ikea.com/us/en/catalog/products/70262197/
Note: The stuffed pillow shown with a different pattern is a sample only. The item's been stuffed with 50X50cm IKEA brand pillow for the rounder, puffier look/feel. That pattern is not available.