Excuuuuuse me... Salt water doesn't cost any more than fresh water. What I think you meant to say was "keep away from power boats."I think the number one thing to keep in mind in keeping costs down as mentioned by many before, is avoid the salt water.
A trip to the jetties or the Gulf State Park pier or the Whislkey wreck is no more expensive than any eqiuidistant fresh water site, and you'll likely see a whole lot more fish.
Rick