Hi hridenoure,
Naturepedic makes a really good crib mattress and its nice to see that you are focused on a healthy bed for your child and considering what IMO are very good options using natural materials.
I think that either direction would make a good choice however if I was considering a wool/cotton option I would likely go with a mattress with an innerspring rather than a futon as it can provide a little better combination of comfort and support as your child gets older (a futon will compress faster and is not as resilient).
Some examples of the types of mattresses that would be suitable for a young child are in post #2 here.
Besides the options in the other thread, some good online choices would be …
A good innerspring with wool/cotton choice such as Pure Echo Natural made by one of our members would also be a good choice.
https://www.mattresses.net/ would also be worth a phone call to ask about building a 6" Dunlop core with wool/cotton quilting (similar to the 8" models they have on the site but without the extra 2") as like many local manufacturers they can build exactly what you may want at a very good price.
Another good option would be to visit a local manufacturer (if you let me know your city I can let you know if I know of any in your area) which are usually one of the best sources of quality and value if there are any near you.
The advantage of a 6" latex mattress with a wool/cotton quilting is that it is so long lasting that as your child gets older and needs more comfort or adjustments to the mattress it is easy to add a softer topper because the core will still be in good condition.
You are also correct about the huge discrepancy in pricing. There are also many instances of “natural” and “organic” and other “green” terms being thrown around very carelessly. While there are Dunlop latex cores that have earned the USDA organic label (CoCo latex is one of them and Latex Green is the other), most of the so-called “organic labels” attached to mattresses all around the internet are not organic and sometimes not even natural. Sometimes it seems like an organic ticking is enough for some outlets to call a mattress organic no matter what else may be in it.
There are also non-organic 100% natural latex cores which are not technically organic but are very “pure” nonetheless and since pesticides are usually only used if at all in the early stages of a rubber tree’s growth before it is used for collecting latex, “non organic” Dunlop latex is also a very good and healthy choice and is less expensive than certified organic. Natural talalay and blended talalay are also very good choices and are usually tested and certified by the Oeko-Tex 100 standard as being safe for babies even though the 100% natural talalay may have slightly lower natural latex content than Dunlop and the blended talalay includes synthetic latex and is not completely natural. Of course what is important for each person is very much a personal decision.
My own tendency would be to go with a 6" 100% natural Dunlop latex core with a wool/cotton quilting unless price was the biggest consideration in which case I would go with an innerspring with wool and cotton layers.
Hope this helps …
Phoenix