How It's Made:
Latex : Latex mattress is made from rubber tree sap.
Memory Foam : Memory foam mattress is made from polyurethane polymers. And it's a little less durable than Latex.
Health Friendly :
Latex mattress is natural and health friendly but not comfortable. Rubber naturally minimizes body moisture, providing warmth in the winter and coolness in the summer. Synthetic foam resists bacteria, mold and dust.
Memory foam mattress is most comfortable, pressure relief but not natural. Foam surface may leave body impressions over time. Latex typically emits odor while off gassing
The price range for both types of mattress is same. It's under $500 to over $3000 and it's depends mainly on how much mattress foam is used.
You may also read buying guide from webmed to pick the perfect mattress for you.