7.5 VDC power supply - on hand
Computer fan - on hand
Magnet from HDD - on hand
25 ohm Pot - 4.29 from Radio Shack
Rocker switch - 3.99 from Radio Shack
Female spade connectors - 1.99 from Radio Shack
Butt Connectors - 1.99 from Radio Shack
Box - 3.50 from local craft store
The screws, washers and nuts I had on hand and don't know sizes and tpi
To hold the PS in place I superglued a couple pieces of ejection rubber I took off an old cutting die. I made a small slot in the back left corner of the bottom half for the PS cord to sit in when in use - tie a knot in the PS cord where it sits against the inside of the box in case it gets yanked.
For wiring I followed Anthony Lopez's posthttps://www.homebrewtalk.com/f51/my-stirplate-cheap-easy-build-86252/