Go down and check coupons out. Remember to check price history if it is available. Best price?
Application, Item GUB G-21 Bottle Cage Adapter/ Conversion, Material CNC Aluminum Alloy Clamp + Plastic Base, Weight 38g, Color Black, Fit for diameter 30.6 — 33.9mm seatpost and handlebar used
Aliexpress
There’re some similar (or not) items on Aliexpress
| Image | Product (link) | Price | Coupons |
|---|---|---|---|
 |
Road bicycle Water Bottle Cage Mount Holder, Anodised Alloy MTB Bike Handlebar rack bracket Seat Post 5 colors 42g | $3.11 | – |
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. One coupon is available. Cool!
Link: Banggood product page
1. ($5.41): AFfbG10
you should apply the coupon 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): BGBFAFF2019, BGCITYADS2019, BGVDay10%off
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for GUB G-21 Bicycle Water Bottle Holder Bracket is here.
Price records source(s): Gearbest, 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)).