There is not a buyer's remorse period. Talk to the store, they will likely work with you, maybe let you into a lesser priced bed.
John Burt - email@example.com - 800-513-6826. Before you contact me read: Information I provide in this forum, and during a free consultation is not legal advice. The information provided is only general information that may or may not apply to you and may or may not be based on current law. I am NOT YOUR attorney until retained by you in writing.
Wow, that is a lot of money for a bed. But, unless it is somehow not living up to what they said it was, you probably don't have any recourse.
As the other attorney said, they might be willing to work something out with you on a less expensive bed, but they are not legally obligated to do that or to take the bed back without something more.