Aliexpress
Click here… to search for Firefly 8S Remote Controller on Aliexpress
Here are coupons that you can use.
Latest coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (8.12 USD): e2bcea
Coupon (8.12 USD): 502C6B
Coupon (8.79 USD): rchobbies8
(CouponsFromChina.com tip: put item in your cart and apply coupon code there after clicking “Proceed to checkout”. Click to copy code and open shop)
Price history and price alert
Here is price history (for all/most countries) for Firefly 8S Remote Controller.
Price records source(s): Gearbest, Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).