Aliexpress
Click here… to search for Gamesir X2 Stretchable Bluetooth Game Controller on Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
Coupon (74.65 USD): BG717000
(CouponsFromChina.com tip: paste coupon code in your cart and click Apply after clicking “Proceed to checkout”. Click to copy code and open shop)
Old coupons (from the oldest to the newest): BG214430, BGHONEY2110, BG04dbb3, BG00ae03, BG1aa6f5, 13f142, BGb6db6d, BG8574cb, BGdeb548, BGb023eb, 00c906, BG1bf36f, BGAlerabat5, BG2a6dfe, BG904ca6, BG95f570, 2203ActiesNL, tRaDetRaCKeR, BGfe690d, BGee1115, BGVDGA07
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for Gamesir X2 Stretchable Bluetooth Game Controller.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).