I need to visualize some scientific calculations. I generally prefer reusing code if there is already a good available instead of inventing wheels each time, that's why I am asking. I need a C# code to draw charts (just outputting a bitmap is ok) of 2d (y=f(x)) and 3d (z=f(x,y)) digital data sets (where any axis can be float, int or datetime), sometimes combined.

If I go here and click 3D in the navigation bar on the left, there I can see what I need. But the cheapest version costs $759 there, looks scary for a hobby project of an east-european student :-(