Seems like they are good prices if you're in the market for a mattress from Tontine.
Edit: Thanks to the following users for their comments:
777
10% CR cashback seems pretty good to me, known brand
Kvaghela
When subscribe for their offers you will get additional 15%OFF so 85%OFF got king size for $464. Thanks OP
Don't know if they stack.
I cannot find any info on dimensions. How thick is it ?