What Types Of Bed To Buy?

I am going to the mall for shopping coming weekend. I told my mother I want to look at the platform beds and compare the price. My old bed already uses for more than 15 years old; I am thinking to buy a new bed for hubby and me. But I am not sure which types of bed to buy it. And my friends told me the platform bed provide quite good support for our back, so I am thinking to do a survey on this type of bed first.