Usually, the cheap stuff does either 2.5D, or 3D, but not both.
For 2D, Vectric's Cut2D and SheetCAM are popular.
For 3D, MeshCAM and Vectric's Cut3D.
You might also look at CamBam, which I think does both.
I don't think there are many DeskProto users due to it's price.