Here's some resourceful (and legal) ways to find Windows 7 legally, cheap and (sometimes) for free. In his just updated ZDNet column Ed Bott runs down several options on ways getting Windows 7 now that its aging a bit. A few take aways: you can still get new computers with Windows 7 installed by exercising downgrade options (free), buying used and refurbished PC's that have Windows 7 preinstalled, finding OEM System Builder software, transferring a license, buying an upgrade license, software subscriptions and more. Some other tricks and interesting tidbits on licensing and other topics make for an interesting read.
Perfectly legal ways you can still get Windows 7 cheap (or even free)