Basically copy coupon, view price history or create e-mail price alert. Do you want to know what the best price is?
19000KV (option) Shaft Diameter: 0.8mm, 1.0mm (option) Configu-ration: 9N12P Stator Diamter: 6mm Stator Length: 3mm Motor Dimension(Dia.*Len): Φ9mm*15.4mm Terminals: JST1.25mm No.of Cells(Lipo): 1S Wire length(include connector): 35mm Weight: 1.7g, KV: 16000KV
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
1. ($15.93): BGJON8
2. ($15.93): BGRCParts8
3. ($15.93): BG8RCToy
apply it in your cart 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): 15SE0603, 502C6B, TTxBG10, AFfbG10, BGVDay10%off, BGAFF10OFF, bGhOnEy10, BGdragonBoat, BGSS10%SW, BGRC902, BgoFErTaSchInA10, Parts8, BgcLuBofErtA10, BGCuponation10, 13f142, BGHONEY2110, BGDAVIS, Tabby20, BG1efeb0, 8Couponsde, MVC8SPRING, 8BGwbg2204, tRaDetRaCKeR, 8wEbgaInS5, pROMo8cuPoN
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for Happymodel SE0603 1S 19000KV RC 1mm Brushless 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)).