Polyamide fiber, Polyester, 260x 150x 75mm.
Just check coupons out (with price alert and history). Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
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.
Link: Banggood product page
1. ($17.99): AFfbG10
2. ($18.59): aff7off
paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/i1u
Old coupons (from the oldest to the newest): 99a5c1, 502C6B, e2bcea, TTxBG10, BGOD1, 2019SPEDM, BGBFAFF2019, BGCITYADS2019
(these coupons are old, so probably won’t work)
Other warehouses/versions
This item is available in 2 another warehouse/versions!
1. China – Xiaomi 90FUN Travel Urban Waist Bag Red ($-3)
2. China – Xiaomi 90FUN Travel Urban Waist Bag Black ($-3)
Price history and price alert
Here is price history (for all/most countries) for Xiaomi 90FUN Travel Urban Waist Bag Blue. The lowest price was: $11.98.
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)).