What nutrients should I get?

[Stan]

I just built an outdoor aeroponic rail system to grow mostly tomato plants . I am using a very large cooler as a reservoir in hopes of being able to keep the water/nute temps at a reasonable level during the summer. All I need now are the nutrients for the plants. I know some nutes especially the organic types can cost an arm and a leg but I'm looking for something on the cheaper side. Doesn't matter what type just as long as it will work for tomato plants.