Usually the price starts from 50% down.
This is a standard practice I've observed from all brands except "Tempur".
So do not get excited by 50% discount, that is the starting price.

Another thing I observed is that, do not get carried away by the hype at the exhibition.
(Usually the exhibition booth rental cost is factored in)
Usually you can get the same or better price if you search around.

Just decide on the exact model you want,
then focus on that mattress model and search / bargain.
You can't go wrong then.

Serta is one of the pricier ones. I understand fully imported.
Simmons is pricier, also fully imported.
Hypnos supply exclusively to the Britain Royal Family.

If compare like this,
Simmons-Best in Malaysia(avalaible in Malaysia)
Hypnos-Best in the world(Queen Elizebeth sleep wan)

All there companies that states "Spinal / Orthopedic / Chiropractic / Back Support / Endorsed / Certified, .... how true or credible is their claim?

If wanna compare prices then find the "manufacturer". They should have a similar model under a diffrent name for their general market.
Everything the same except model name.
That is what I did and it works. Saved a lot as I was looking at a relatively pricey model.

Getha is manufactured and sold by the same entity, do not think they have different name for same model for other resellers.
This re-naming models usually cater for big outlets like MFO.

Here is my 15" (I think 16") thick Mattress.
Silentnight's Buckingham

http://forum.lowyat.net/topic/1918768/+620

Same manufacturer as Silentnight. 1 company 2 brand.

The cost for the seller is the same, top up minimal amount for frame is only considered cheap if you have did your research by inquiring and comparing to at lest 2 diffrent alternative seller for the same or equivalent product.