Hi Schurke1337,
Hopefully some of the members here that have specific experiences with multiple mattress purchases from the manufacturers or retailers they purchased from will read this and share their experiences with you.
My only caution would be to make sure you make meaningful comparisons based on your personal value equation and the specifics of the mattress materials and construction at any “final price” because in many cases the “value” of a discounted price may still not be nearly as good as another manufacturer or retailer that doesn’t provide a discount for a multiple mattress purchase because they are already at the lowest possible price they can provide (although I would always ask if I was buying more than one mattress).
Some of the better local options in the Pittsburgh area I’m aware of are listed in post #2 here.
Phoenix