are you wanting to start cheap because you arent sure if you'll like it? or starting cheap just because thats the way you want to start?
For $70-80 you are quite limited. I would suggest getting a rod that will have a good warranty so that if you break it, it will be replaced.
Redington has good rods for beginers as well as a good warranty.
A cheap reel will get beat up by the saltwater even if you take very good care of it. A pflueger medalist should run you about $30 or so depending where you find it. It will do just fine.
A basic all-around rod weight for the salt is a 6wt.