Started life as a "broken" desktop that I got from a client. The broken desktop had a bad motherboard but most of the other parts were fine. It had a Intel i7 3770 ( sweet! ), 500gb 2.5" 7200rpm drive, dvd drive, and a Windows key.
I scraped the old case ( kind of beat up ) and bought the Zalman ZM-T1 plus as I had not ever used it before and it was cheap. I like to try and buy a different case every time I do a build for myself or something I know I'm going to resale. Lets you see new and different hardware. The Zalman came with a 80mm exhaust fan, but no intake fan on the front. I had a 120mm cooler master fan that was from a old box, so I threw that in the front.
The psu in the old case was a no name 300 watt'er, tossed it and got a EVGA 400 watt, was sub $30 and I've used that same psu a lot with zero issues.
I needed a new motherboard as the donor desktops motherboard was cooked. I went with a ole standby, MSI H61M-p31, its super cheap and gets the job done.
I had a Corsair XMS3 kit from a build I did a couple of years ago and had upgraded, 8gb, plenty, done.
The old cpu fan was super dirty and had one broken mounting tab, so I picked up the generic one from newegg for $10.
I got the GTS 450 from a friend for free, so why not, tossed that in there too.
I figured with a i7 chip, i wanted a SSD ( ya, ok I always want a SSD ) for the OS and applications, grabbed one from my old upgrade "graveyard" threw it in the bottom of the case and mounted the donor 500gb 2.5" to the back side of the motherboard tray for mass storage.
Installed Windows 7 and then did the free upgrade to Windows 10. Overclocked the i7 to 3.9ghz. Ran some basic tests and AIDA64, cpu temps are good with peaks of 65c. Overall pretty happy with it for $ I've got in it.