It depends on what exactly you are looking. Since sleep is a good investment, it a worthwhile investment to buy a good bed (You can think of it as 60 cents per night of sleep for 5 years etc.). I really like the sleep number – their cheapest one with their mattress cover is awesome! Many people also swear by Tempurpedic (esp. the Rhapsody with a down topper) beds especially for people who work long shifts or for new parents and anyone who doesn’t get much time to rest but need good sleep in the few hours that they do.
I love my mattress from Tuft and Needle because it’s really affordable, and it also helps prevent me from rolling into the crevice if someone sleep next to me.
Stearns and Foster pillow top is also really awesome; Latex mattresses are the best!!!! We recently bought from Plush Beds and they are amazing.
The Casper mattress is really amazing. And some of my family members love the custom Helix mattress.