According to my DB the lowest price is $40.49 for 16W 5V Foldable Solar Panel ETFE (in Banggood). Basically copy coupon, view price history or create e-mail price alert. What is the best price?
Open Circuit Voltage: 6.8V, Working Current: 2.9A, Folding Version: 2 fold, Expanded Size: 460*240*3.5mm, Dual USB output control: USB 5V3A supports multiple charging protocols, Product Power: 16W, Short Circuit Current: 3.19A, Weight: 0.25KG, Folded size: 240*200*30mm, Working Voltage: 5.5V
Latest price update (UTC time):
Banggood ($40.49)
Banggood warehouse is located in China. Low/high price? This price is higher than average price ($29.24) for this item. We have found one coupon for this product!
Link: Banggood product page
Price without coupon: $44.99
1. ($40.49): BGAMMT03
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG9c7cb8, BGSCM11, BGCarEle5, BGLMQ15, BGc37486
(these coupons are old, so probably won’t work)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for 16W 5V Foldable Solar Panel ETFE.
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)).