Just check coupons out (with price alert and history). Do you want to know what the best price is?
Color Beige /grey, Shape Triangle, UV blocking rate up to 95%, Material HDPE
Aliexpress
I could not find it on Aliexpress. Click here to search by yourself.
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in Europe 
. I don’t really know if this price is reasonable, coz there’s no price history in my DB.
Link: Banggood product page
1. ($20.92): Cuponation9
2. ($21.15): BG8ReviTrage
3. ($21.61): BG00c906
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): BGe46870, BG7280ff, Tabby20, BG1efeb0, MVC8SPRING, 8BGwbg2204, 2203ActiesNL, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BGJUNEGSG9
(these coupons are old, so probably won’t work)
Price history and price alert
Not enough data to show price history chart… $14.99 is the only recorded price. It was not cheaper than that since we have saved it in DB.
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)).