For a graph under $200 I would just set it up and let it rip. A graph at that price point isn't gonna have a whole lot of features to it. I mean, I guess you can tune your 2D sonar some, and I think some come with down scan. Im not trying to burst your bubble here, just stating that you won't get a whole lot out of it.
Good luck with your search.
"If people concentrated on the really important things in life, there'd be a shortage of fishing poles." - Doug Larson