We went to a mattress store not too long ago (debating on downsizing from king to queen). It was nice because they weren't paid on commission so he wasn't pushy and he told us when we're ready to buy to ask for last years model. They are way cheaper and typically exactly the same as the new model just a different accent color.
I've bought them at BJ's and Sam's clubs. They were excellent. The one I bought at Sam's was 13 yrs ago and it us still in great shape. The one from BJ's I've had a year, I love it.
Also check Big Lots if you have one close to you. They run sales where you buy the mattress and get the box spring for like ten bucks. No delivery that I know of, so you'd have to take it home yourself.
I would just but it on Amazon. I just got a King size memory foam mattress with great reviews for $600. I like that you can read the reviews on their products to see if they are good or not. I used to go by Consumer Reports but I find myself agreeing with actually user reviews rather than some "expert".
bedinabox is the best. We have a queen that cost us 1/3rd of what we had been ready to spend at Matress Firm on a Tempurpedic. My best friend has a different model CA King and they love theirs as well.
Do NOT buy any matress before you check out what they have to offer. Setup was super easy. Just as it sounds, the matresses are vacuum sealed and wrapped, stored in a bag, then stuffed in a box and shipped to your door. American made, fast, great customer service.
We just ordered a pair of their pillows to go with our matress.
we just downsized from a king to a queen our last mattress was bobs discount furniture,and it's been in rough shape for about 2 years, it's 14+ years old..so not bad. Just bought from sears.com- we went to the store and tried them all out ,then went home,and ordered online,saving over 100.00 from the in store 'sale' anyway- free delivery,free takeaway of old bed (priceless!) and looking forward to a nice firm matress again.... the prices were competitive for what we were looking for....
FWIW, there is no way I would personally buy a mattress without being able to try it out first,it is so different for different people..... we must have tried 20 mattresses out before we agreed on what we wanted....
A few years ago we switched from a Sealy to foam mattresses from ikea. My twins have fad theirs for 7 years and they're still in great condition, so we decided to try ikea for our bed. Love it, and a lot less then other foam mattress brands I looked at.