Got the PC for free with some old Pentium G620 and 2GBs of RAM, a AMD Radeon HD 6750 and an ugly old case.
First thing I did was order some SO-DIMM to DIMM adapters from AliExpress for a couple of dollars because I had some old SO-DIMM 16GB Transcend kit from a dead 2011 Mac Mini.
Next thing was to order a Xeon E3-1220, also from AliExpress for $12, because it was an upgrade and I was doing it for cheap to have a desktop PC while in college.

After that, I decided that the case was ugly and I bought a Zalman S3 brand new for $30, as it was cheap, had okay cable management and a acrylic side panel for some RGB strips that will come a bit later, and with it I bought 3 Akyga 120mm Molex fans for $11. The last two upgrades were to buy a RX580 4GB card used for $100, a new CPU cooler(Arctic Freezer 7 Pro) and an old Thermaltake 630W semi-modular power supply from my old pc.

Future mods are a cheap custom water cooling, I have parts ordered from eBay and AliExpress, now just waiting for them to arrive and install them, along with a used Z77 motherboard I bought for $86, I think water cooling will cost roughly around $80. I would like to buy an i7-3770k or a Xeon E3-1245 for some more threads and a higher clock speed, but they are both expensive for now, and of course, the new motherboard has more RAM slots, so 16 more gigs will come for a total of 32GB.