for firmware update.
Basically copy coupon, view price history or create e-mail price alert. What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($10.79): BGRADIORU
2. ($11.03): BGRCParts8
you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Additional Banggood coupons: first page and second page
Old coupons (from the oldest to the newest): aff7off, rchobbies8, TTxBG10, e2bcea, 502C6B, d8f2bb, Parts8, BGaDmITAd, BGBFAFF2019, BG9NY, 2020CNY, BGVDay10%off, BGFS12, BGFKY11, bGhOnEy10, BGflysky11, BGRCRR9, BGAFF10OFF, BG11SHOP, BGDAVIS, 13f142, BGradio9, BG70e5fc, BGGAL8, BG1efeb0, 8Couponsde, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, BGJUNEGSG9, BGRCT10
(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
Price history (for all/most countries) for FlySky RC Data Cable FS-i6 FS-T6 is here. The lowest price was: $3.31.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).