$7.22 – 5V 400mA Solar Panel 2W (Banggood, Aliexpress: Working voltage: 5V, Working current: 0-400mA, Process: EVA lamination, Output power: 2W, Output port: USB, Product size: 157 * 94mm, Wafer: class A polysilicon, Conversion efficiency: 18.8%, USB cable length: 50cm (the best price with coupon)).
I am monitoring price for 5V 400mA Solar Panel 2W and it is for $7.22 now (in Banggood). Just check coupons out (with price alert and history). Let’s see what best price is ATM.
Latest price update (UTC time):
Banggood ($7.22)
Banggood warehouse is located in China. I’m afraid that there’s no working coupon in Banggood. Isn’t it too expensive? It looks like it’s a good price (lower than average ($7.30)).
Link: Banggood product page
Price: $7.22
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/feV
Old coupons (from the oldest to the newest): BG589b2e
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
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.
Price history and price alert
Here is price history (for all/most countries) for 5V 400mA Solar Panel 2W. The lowest price was: $7.16.
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)).