How to store my O/U

I was wondering if the bumpy foam in the cheapie cases can cause any damage to the gun due to the chemical makeup of the foam? I bought a really cheap [$11.88] hard plastic case with the bumpy foam from Wal-Mart just to carry my gun back and forth from the range. Could it hurt to leave it in the case between trips?

Thanks for all the posts on the foam lined case transportation/storage question. I'm just using the case to transport to and from the range. I just didn't know if leaving it in the case for a day or two might cause damage over time due to the chemical makeup of the foam. Being in Colorado, I really don't see rust on anything given reasonable care. As you can tell from my equipment, I'm on a real tight budget.