The current price for OEM Windows 7 Professional at Newegg, for example, is $140. You can find OEM System Builder software from dozens of online merchants. However, the license agreement with those copies explicitly prohibits you from using that software on a PC you build or refurbish for your own personal use. Under Microsoft's arcane licensing rules, you can legitimately purchase OEM copies of Windows 7 (any edition). OEM Windows software for new or refurbished PCs

I don't recommend taking a chance with random sellers on eBay or Craigslist-not when there are so many well-established merchants that offer proper warranties and return policies, as well as an assurance that the underlying Windows license is legitimate.

Staples has a similar selection in its online store.

Many are too old to recommend except for diehard bargain hunters, but if you know what you're looking for you can find perfectly good hardware that costs less than you'd pay for a retail copy of the Windows 7 version it includes.

Newegg has an enormous selection of refurbished PCs as well.

Tiger Direct offers 'off lease' Windows 7 PCs for as little as $100.

Other online sellers with similarly extensive selections include the following: Amazon-owned Woot, for example, always has lots of choices in its Computers section, although you'll have to dig into the specs to confirm that the operating system you're looking for is included. There are plenty of sites where you can find 'factory reconditioned' PCs for sale at legitimately low prices. Used and refurbished PCs with Windows 7 preinstalled

Big online retailers that serve business markets should have similar selections covering a wide range of brands and the full spectrum of prices.

Microsoft windows 7