Model: Nazgul 5140, Color: Transparent Grey / Transparent blue / Transparent red /Yellow, Item Name: 5140 5 Inch Durable 3-Blades Propeller, Quantity: 6 CW & 6 CCW, Weight of Single Prop: 4g, Blades: 3 blades, Brand Name: iFlight, Mounting: 5mm center hole, Material: polycarbonate.
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 coupon code price check (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($9.55): BGRCParts8
2. ($9.55): BGMatt2022
3. ($9.55): BGToys8
apply it 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): BGAFF10OFF, BGDAVIS, BGHONEY2110, Parts8, BG1efeb0, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, BGToys1, BGRCT10, BGJUNEGSG9, Cuponation9, 9OFFSUMMER
(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
Check out price history chart (for all/most countries) for iFlight 5140 NAZGUL 5Inch RC Propeller. The lowest price was: $4.49.
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)).