Hi RazzleDazzle,
I’m not sure what you’ve read since you found the site but just in case you haven’t read it yet … the first place to start your research is the mattress shopping tutorial here which includes all the basic information, steps, and guidelines that can help you make the best possible choice … and perhaps more importantly know how and why to avoid the worst ones.
Two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort”, firmness, and PPP (Posture and alignment, Pressure relief, and your own Personal preferences) that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well he will sleep), durability (how long he will sleep well), and the overall value of a mattress compared to your other finalists based on all the 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).
There are some very general guidelines about what to expect in different budget ranges in this article.
As far as what you “should” be spending there’s really no definitive answer to this but I would suggest as much as you can comfortably afford … within reason and within limits of course. You will find better quality and higher performance materials and components and more sophisticated and complex designs in higher budget ranges but once you reach about $3000 or so (in US dollars and in queen size mattress only or the equivalent in a king size which are generally about 15% to 25% more) then any realistic or meaningful performance benefits that go with higher prices than this may be minimal and there would need to be a compelling reason and obvious benefits that you can identify in “real life” to spend more than that. Even then I would make some very careful value comparisons with other similar mattresses that are available to you based on the parts of your personal value equation that are most important to you because it’s quite likely that you will be able to find a high quality mattress in a lower budget range than this that will work very well for you.
Again it’s not really possible to generalize because it depends on the specifics that are available at the store you are purchasing from but if you are dealing with a good manufacturer or retailer that sells suitable bedframes and foundations then I would tend to purchase them where I purchased the mattress unless there is an obvious or compelling reason not to.
Phoenix