There's no doubt that memory foam beds provide many benefits, like excellent support and good, healthy sleep, along with the fact that while it contours itself to you as its substance is softened by your body heat, it regains its original shape when you get up. If you can't really afford a full bed, perhaps you might consider a foam mattress topper instead. You might call it something of a mattress enhancer.

But for the sake of your future comfort, you should be aware of some of the drawbacks of foam mattress toppers as well. The reason why memory foam works so well in the first place is that the top 3 inches or so heat up and will change shape, while the lower layer is not affected, remaining cool and firm. This is how much of the good supportive effects are derived. If you don't already have an existing mattress to provide similar underlying firmness, then the good effects of the foam topper will undoubtedly be lost.

You should also realize that your own mattress must not sag in the middle, but is required to be uniformly flat, not to mention firm. Even visco elastic memory foam won't be able to keep from sagging into the underlying mattress if it has dips in it. When your body heats it up, the foam mattress topper will acquire even more of a sag in it as it softens and changes shape. In the end, you might sleep less comfortably than you had expected, and any good effects you might have received from your topper will vanish.

Since a faulty underlying mattress might rob you of whatever benefits you hoped to gain from your foam mattress topper, you may need to evaluate whether it's a good idea to go that route. If it's going to cost extra to make sure your underlying mattress provides the support needed to make the topper effective, then perhaps it would be wiser to accept the extra expense and buy a complete memory foam bed instead.