Build this mini-itx system almost 3 years ago and managed to keep it clean by covering the bottom with a dust filter from AliExpress, most internals were bought second-hand with the exception of the processor (i5-6500), the motherboard (ASUS B150I Pro Gaming/Wifi/Aura) and the power supply (Corsair CX550). The entire system including the 1070 (which I bought before the mining craze) set me back around 700-800 eur. Costume sleeving and a backplate for my graphics card were unfortunately not within my budget, but I still really like the end result!

Peripherals have been added later, my keyboard has a (very) minor mod: replacing the Cooler master Key caps with portal keycaps.