Anyways, the typical pillow is filled with polyfil stuffing which causes the standard pillow life cycle as described above. Then there is the foam pillows that your head sinks into, but it bounces right back up in about a minute. The problem with these pillows is I just find it uncomfortable to have my head resting in a mold of my head. Perhaps I'm slightly claustrophobic.
As you can see in my pictures, I took some craft foam and cut it up into cubes. To cut the big block of foam I use a bread knife. I keep one around just for craft purposes. When I got all the cubes cut up I put them in the center of the pillow as shown above. Then I just stitched up the side of the pillow, and my pillow has not gone flat since. Keep in mind there is various firmness levels of craft foam, and the thickness of the foam makes a difference as well. I like a really thick and firm pillow, so the foam I used here is for a chair cushion but I didn't use very much of it. However, I made my husband a travel pillow with a similar technique and used the type of foam you'd find on top of a mattress. Its all a matter of how much give you want your pillow to have.