Aliexpress
Here are coupons that you can use.
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – iMars SP-B135 135W Foldable Solar Panel 135W [EU] (-3 USD)
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China. So I have checked for active coupons (all category coupons and old ones), but there was no working coupon in Banggood.
Link: Banggood product page
Price: -3 USD
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BG10OFFAFF1, BG0a2117, BGiMarsSP135, BGiMars135ar, BG30dac7, BG613CZ01, BG613eu, BG2ae107, BGa33686, BGa023fb, BG350b38, BG80613A02, BANGGOODSD, BG613ESC01, BGbe24aa, BG40704a, BG613CZC01, BG08c9e2, BG1eb062, 00c906, BG00c906, ADMITAD2212, 2022ACTIESNL, BG0e5acc, BG5166bb, BGCarEle1, BGSKUH80613A, BGdaa42a, BG1eb1b7, BG66360, BGa1f887, BGdf5ef3, BGdf5ee4, BG653635, BG25e162, BG7581bd, BGb8fc25, BG5d1832, BG0a784e, BGd87ac3, BG9c60c1, BG2d849b, BG473ae0, BG555bf9, BGa41ff2, BG20iMars, BG7d530e, BG77a4b2, BGdcbfa8, BGiMars2022
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Europe – iMars SP-B135 135W Foldable Solar Panel 135W [EU] (-3 USD)
Price history and price alert
Here is price history (for all/most countries) for iMars SP-B135 135W Foldable Solar Panel 135W.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).