In my opinion this is the best, & by far the easiest DIY GoPole to make. It can made in under 2 minutes for about $20. LINKS TO PARTS BELOW.
I am an Amazon affiliate so i get a small kickback on every purchase.
Monopod – (Vivitar $12.99) https://goo.gl/qX5jH2
(Amazon Basics $14.99) https://goo.gl/HJ555X
GoPro Tripod Mount – https://goo.gl/yggRO0
Socket Set Screw (Cup Point) – Home Depot – $0.98 – https://www.homedepot.com/p/Crown-Bolt-1-4-in-20-tpi-x-1-in-Stainless-Steel-Socket-Set-Screw-2-Piece-per-Pack-812228/204274249
OR from Menard’s – https://www.menards.com/main/building-materials/drywall/screws/specialty-screws/1-4-20-x-1-1-2-slotted-headless-set-screws-1-pack/p-1769728-c-8938.htm