Zebco has been making a saltwater model for many years, I don't know how the new ones are, but the best fisherman that ever came out of New England, used nothing but, when he wasn't fly fishing.
South Bend makes an entry level SW pushbutton reel that we carry at the shop. It goes for about $25-30. Sold a few and never heard any complaints. Has a fair amount of stainless components I believe, and is spooled with 20lb. test. It is what it is, however, so I wouldn't head out for school tuna with it.