A 5 pound pad is the first thing you'll leave in the dumpster after a day of hiking.
A light foam pad like the Terma-Rest RidgeRest comes in at half a pound, get two and it's a pound, yet a rather bulky package to strap to a pack.
So how about a hybrid - one foam pad and a thinner inflatable on top?
Any average inflatable from Pacific Outdoor or other second tier brands will be 1.5 pounds and cost less than $80 if you shop around. Add to that a foam pad and you are still 3 pounds ahead, while you have double the protection and still foam under you even should you puncture the inflatable, which is less likely having that layer of foam below.
