Just check coupons out (with price alert and history). What is best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Weight 9.8g, Configu-ration: 9N12P, Maximum current (180S) 13.38A, Stator diameter: 14mm, KV: 3850, No. of cells: 2 ~ 4S, Stator length: 4mm, Max power (Power (W) 180S): 214, Motor size (width * height) Φ18.3 * 14.5mm, Shaft diameter 1.5mm, Idle current (10) @ 8V (A) ≤0.51, Internal resistance 0.213mΩ
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($21.01): Cuponation9
2. ($21.24): BGJON8
3. ($21.24): BGRCParts8
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 and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): AFfbG10, BGAFF10OFF, BGTT10, bGhOnEy10, BGdragonBoat, BGSS10%SW, bgshOOp10, BGRC902, BgoFErTaSchInA10, BgcLuBofErtA10, BGCuponation10, BGDAVIS, BGHONEY2110, Parts8, BG1efeb0, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN, BG8RCToy, BGToys1, BGRCT10, BGJUNEGSG9, 9OFFSUMMER
(these codes were not working in latest coupon update, but you can check them out anyway)
Price history and price alert
Here is price history (for all/most countries) for GEPRC GR1404 2-4S RC Motor.
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)).