For only $50-$60, Amazon has the GOOD Pelican foam. Pack consists of 3 pieces. Use what you need to keep the rest for the next time you need it. This is what I got earlier in the year.
Pelican 1701 Replacement Foam Set (3) for the 1700 Cases https://www.amazon.com/dp/B000FULDHE/?tag=accuratescom-20
You can buy a case with the foam in it for that much off of eBay. If I was buying a thicker [say >5"] case I'd be asking about the foam before I bought.