Aliexpress
Click here… to search for 17L Backpack Laptop Bag on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. You can get coupon down below.
Link: Banggood product page
Coupon (35.16 USD): BGc363fd
(CouponsFromChina.com tip: 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
Old coupons (from the oldest to the newest): 8BGwbg2204, tRaDetRaCKeR, BG2bb7a1, BG5d2ea4, DealBGimpact, Cuponation9, 9OFFSUMMER, BG073996
(probably won’t work, but you can try them out)
Price history and price alert
Check out price history chart (for all/most countries) for 17L Backpack Laptop Bag.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).