Latest update shows that Dual USB ETFE costs 33.29 USD (in Banggood). Go down and check coupons out. Remember to check price history if it is available. What is the best price?
Latest price update (UTC time):
Banggood (33.29 USD)
Banggood warehouse is located in China. Is it cheap? From what I can see this price is higher than average price (28.32 USD). There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Price without coupon: 36.99 USD
Coupon (33.29 USD): BGAMMT03
(CouponsFromChina.com tip: put item in your cart and apply coupon code there 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): BG8b7b16, BGCarEle4, BGSCM11, BGCarEle5, BG2992f6, BG845979, BGLMQ15, BGCAR639
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Aliexpress
Click here… to search for 14W 5V Dual USB ETFE Solar Panel on Aliexpress
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for 14W 5V Dual USB ETFE Solar Panel.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).