If I buy a desktop with no hard drive and I buy a brand new hard drive what is the cheapest way to get windows 7 on it?

[zl44]

I am looking to buy a barebones desktop with a processor and then add the ram and hard drive and resell for a decent profit but my concern is that it would be too expensive to get windows 7 on the new hard drive so what would be the cheapest way for me to get windows 7 on there?

 

[zl44]

Or would it just be cheaper to buy one with windows 7 installed and switch the hard drives then use a recovery disk? I'm sorry for my ignorance I am only 16 and new to this kind of stuff.