Aliexpress
Click here… to search for Solar Power System Kit 18V 4000W 12V to 220V Inverter 30A [EU] on Aliexpress
Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in Europe 
. Uhm… There’s no price history (in my database) for this product right now. We have found one coupon for this product!
Link: Banggood product page
Coupon (67.65 USD): BGCarEle4
(CouponsFromChina.com tip: apply it in your 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: 67.65 USD.
You can set price alert (for Banggood).