Futon mattresses are the most important and useful part of futon, they can even be used quite comfortably without the frame or cover, although those do add a little bit of comfort. For generations these mattresses have been unrolled onto a bare floor turning any room into a comfortable bedroom. The frame that is commonly associated with futons nowadays is a recent adaptation of what is traditionally considered a Japanese invention, though bedrolls have been common throughout history.
The quality of the mattress will determine how comfortable the futon will be for sleeping, sitting, and lounging as well as how long the cushiness will last. Unlike a regular mattress which is stiff laterally, futon mattresses have to be flexible enough to fold and roll up when necessary.
This is how the bed can also become a sofa and switch right back around with a simple movement of wood. When a frame is not involved they can easily be rolled away and stored out of sight and virtually eliminating the need for a bedroom. This is useful for college students, small apartments, and for the forward thinker that has realized there really is no need for a room dedicated to sleeping however important it is. In many large Japanese cities this style of living is embraced and often necessary. Expect the trend to continue as modernization spreads and populations grow.
Some important factors to consider when purchasing a mattress for a futon is the firmness, flexibility and thickness of the mattress. Ask yourself a few simple questions before selecting the right mattress. What is wrong with your current mattress? How long do you plan on using your new futon mattress? Will it move with you to a new place or simply be sold and replaced? How long do you want the mattress to last? Do you sleep on your back, side or, stomach? How tall and big are you? Will a large mattress even fit into your apartment or house? There are many factors that influence a mattress purchase.
Often the determining factor is directly related to your budget. An important thing to remember is the cost per year of the mattress. A cheap one might only last for a couple of years, which could make it cost more per year than a more expensive but longer lasting comforter. It may be a better deal to buy a more expensive but better built mattress that will last for 20 years.
Don't forget the pillow either, this is just as important as futon mattresses themselves. Look for support and comfort, it doesn't need to be expensive, but often a higher priced pillow with be comfortable for a much longer time. Comfort is the goal, so don't skimp here.