place to make a 3D chart with a formula?

that's pretty much what i need, looks... complicated, and i need to pay? if so i can't get access to it then ._.

The viewer itself (http://www.dpgraph.com/graph-viewer.html) is actually free. It isn't that complex to use, but if you want you can use Wolfram|Alpha or Mathematica to produce the charts as well (albeit the latter costs money).