Basically copy coupon, view price history or create e-mail price alert. Best price?
Name: Glass Polishing Kit, Model: 520396, Polishing cloth size: 28mm*28mm, Backing Pad size: 75mm/3inch, Rayon Felt Polishing Pad size: 75mm/3inch, 45mm(Length)*10mm(Thread dia.)*8mm(Shank dia.), Thread Drill Adapter size:
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
1. ($7.49): BGGines
apply it in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BGHPT15
(these coupons are old, so probably won’t work)
Price history and price alert
Check out price history chart (for all/most countries) for 75mm Glass Polishing Kit.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).