Aliexpress
Click here… to search for Monocrystalline 80W 18V Flexible Solar Panel Waterproof [EU] on Aliexpress
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. There is one coupon right now! Check this out.
Link: Banggood product page
Coupon (51.84 USD): BG845979
(CouponsFromChina.com tip: coupon code has to be applied in shop’s cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Price history and price alert
It’s a new item in our database, so I can’t create price history chart. We have saved this price in database: 51.84 USD.
You can set price alert (for Banggood).