I needed a stationary sander, but the ones in the store costing $100 were just too expensive for me. I decided to make my own station, using some cheap electronics and my acceptable designing skills...

The parts for this sander cost under $20 in total. Here is the parts list:
-12V 5A Power Supply
-775 DC Motor
-DC Speed Controller
-Wires
-Scrap piece of wood for the base

You will also need equipment to solder the wires onto the motor, as well as some M3 screws.

I am too lazy to copy 3 links, so here is the link to my DC Speed Controller Case. You can find the links to the parts in the description: https://www.thingiverse.com/thing:3622972
You can find a 775 DC Motor practically anywhere on the internet. I bought mine from Banggood.

OR

You can buy them through these Banggood links (these are affiliate links, which means that I get a small percentage of the sale. There are no extra costs for you, so this is the easiest way to support me as a young maker :) )

775 DC Motor: http://bit.ly/37elpMX

DC Speed Controller: http://bit.ly/2ZDC8Xy

Power Supply: http://bit.ly/2rzeAq2

DC Plugs: http://bit.ly/39nEv51 (You could just buy one female DC plug, but i think it is worth having a set of 10 pairs for future projects.)

Some accessories you need to make this (these are just my recommendations, if you already have this, you are good to go.) :

Cheap, good wires: http://bit.ly/2ZvLgxf (I used 14AWG wires in this project)

Solder: http://bit.ly/2Qrhohp (Out of all the solder types I have tested from China, this is my favourite go-to solder. Makes nice and shiny joints.)

TS100 Soldering Iron: http://bit.ly/37jqjrQ (I have not tried this one, but this is apparently the "mainstream" soldering iron which the majority use.)

Heat Shrink Tubing: http://bit.ly/37jqQKm (This will last you a long time, and cover all your heat-shrinking needs.)

Thank you for your support! :)