Mattress Brands Are Majorly Marked Down for Black Friday—Including Casper and Purple.Investing in better sleep doesn’t have to break your budget. These online mattress brands are offering incredible mattress deals:.Best Affordable Luxury: Saatva Classic, $1,199 at saatva.com.Best Memory Foam: Casper Original, $931 at casper.com.Best for Side Sleepers: Nectar, $799 at nectarsleep.com.Best Hybrid: DreamCloud Premier, $1,199 at dreamcloudsleep.com.Best Cooling Mattress: Helix Midnight Luxe, $1,649 at helixsleep.com.Most Responsive: Leesa Original, $849 at leesa.com.Best for Back Pain: Purple, $1,049 at purple.com