[jman4747]

How large are you expecting your assembles to be? $500-700 new may not be enough. Also I believe a desktop will give you more power for the price and would consider that first before a laptop. CAD is really meant to be done on a workstation PC which for laptops starts at something more like $1,200 maybe.

In short your best bet is to get them donated. An interesting tactic I thought of was to search job listings in your area for companies who need people who know CAD or any other skill that would require the use of a computer with that kind of power. Then ask them for the old ones they have. Also any engineering school at a university near you.

Example Lenovo
Laptops: http://shop.lenovo.com/us/en/laptops...nu-id=w_series

And desktops: http://shop.lenovo.com/us/en/worksta...nu-id=p_series

PS I'm writing this on a Lenovo W540 laptop.