Here is a link to someone with a OneCNC for sale. Now granted it is not Autocad, and it is not cheap cheap, but if you want CAM eventually, then I think it is an excellent value. Plus, you can resell your OneCNC, the next user pays a $500 fee and he's registered just like the previous user was.
This version of OneCNC has the solid modelling package included, which (solid modelling) I would highly recommend to anyone getting a cad package nowadays.
http://www.cnczone.com/ub...ic/27/535.html