The most cost effective way to nest parts manually is with SheetCam.
At just a glance & without actually learning to use it. Sheetcam doesn't look all that great. It is however, for the cost, just about the best thing out there for aiding in nesting of parts.
Once you learn to use it & it's features, it's pretty amazing how quickly you can nest a 4' X 8' sheet of parts.