I would decide what size of box that I want to lift first..................deeps, mediums, or shallows.
Then, call one of the supply houses that is close to you (we really don't know where you are yet) and have them tell you what frame size and foundation that will "fit" your box.
After that, they will probably ask you if you want to go with grooved tops and bottoms, grooved tops and divided bottoms, wedge tops and divided bottoms, wedge tops and grooved bottoms, etc., etc., etc. And that's just the frame style!!
Then, what type of foundation (if any) do you want to use? Plain, wired, plastic, thin, etc.
Most of the good suppliers can make recommendations once they know what you want to do with the hives.
Sorry for the confusion!