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 (5.28 USD): BGGAL8
Coupon (5.28 USD): BGJON8
Coupon (5.28 USD): BGRCParts8
Coupon (5.28 USD): 8Couponsde
(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)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BGAVANes, TTxBG10, BGemaxParts, 2019SPEDM, AFfbG10, BGVDay10%off, Parts8, BGAFF10OFF, bGhOnEy10, BGdragonBoat, BGSS10%SW, BGRC902, BgoFErTaSchInA10, BgcLuBofErtA10, BGDAVIS, BGHONEY2110, Tabby20, BG1efeb0
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Price history (for all/most countries) for Emax AVAN Flow RC 4x Propellers 2206 2207 2306 is here.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).