Memory foam: why so expensive?

A question about : Memory foam: why so expensive?

Just stayed in a hotel in Europe which had a 2 inch topper mattress over the base mattress. Don't know if it was memory foam, but it was very comfortable.

So I thought I might buy something similar to rejuvenate my old mattress at home.
But why are memory foam toppers so expensive? Even the ASDA ones are 50 quid?

It's only a bit of foam, isn't it?

Best answers:

• Don't know.
  But it cost about Ј35 at amazon/ ebay for double.
• Ј50 is very cheap.
  It's not just ordinary foam. Even with ordinary foam there are around 100 different types.
  Memory foam is a high density slow recovery product, which like normal foam can come in different grades.
  I've seen toppers at well over Ј400.
  You get what you pay in life.