Aliexpress
Click here… to search for Gosund CP1 Smart Socket on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (11.25 USD): BGAFF10OFF
Coupon (11.50 USD): 13f142
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply 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): TTxBG10, 2019SPEDM, BGGosund10, bgssaff9, BG855Gosund, AFfbG10, BGBFAFF2019, BGCITYADS2019, BGVDay10%off, BGHOMEG12, bGhOnEy10, BGdragonBoat, BGSS10%SW, BGHome15%, BGHOMEA15%, BgcLuBofErtA10
(probably won’t work, but you can try them out)
Price history and price alert
Price history (for all/most countries) for Gosund CP1 Smart Socket is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).