Hi DonJuanFromNom,
Hopefully The Toddler will see your post and share their comments and feedback but I would be very cautious about using other people’s experiences or reviews on a mattress (either positive or negative) or review sites in general as a reliable source of information or guidance about how you will feel on the same mattress or how suitable or how durable a mattress may be for you and in many if not most cases they can be more misleading than helpful because a mattress that would be a perfect choice for one person or even a larger group of people may be completely unsuitable for someone else to sleep on (even if they are in a similar weight range or have a similar sleeping style) and reviews in general certainly won’t tell you much if anything about the suitability, quality, durability, or “value” of a mattress for any particular person (see post #13 here).
I don’t know if it ever goes on sale but the idea that they raise the price during peak buying periods sounds somewhat ridiculous to me and it more than likely just a tactic to create a “sense of urgency” and get you to buy the mattress before they “lose” you to another store.
Unfortunately there isn’t a “formula” that can be used to assess or “calculate” the value of a mattress because there are so many different variables and criteria involved that can affect the price of a mattress that can each be more or less important to some people and not to others who may have completely different criteria or definitions of “value” but the “value” of a mattress purchase is always relative to how a mattress compares to the other finalists you are considering or to other mattresses that are available to you in your area (or online if you are also considering online options) based on all the parts of your personal value equation that are most important to you. If you are only seriously considering one mattress at one store then it would be difficult to assess the “value” of the mattress because you wouldn’t have anything to compare it to.
There is also more information about the 3 most important parts of “value” of a mattress purchase in post #13 here which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on suitability, durability, and all the other parts of your personal value equation that are most important to you (including the price of course and the options you have available after a purchase if your choice doesn’t turn out as well as you hoped for).
Phoenix