Motor: 8520 Brush Motor, Batterry: 3.8V 500mah Lipo battery, Flight time: 6 minutes.
Basically copy coupon, view price history or create e-mail price alert. 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 and price update (UTC):
Banggood
Banggood warehouse is located in China. Only one coupon available!
Link: Banggood product page
1. ($108.89): BGRCEachine
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): bb5de1, quad35, 812c92, a16b7c, AFfbG10, BGEachine, BGEachine11, BGCITYADS2019, BGEachine10, 2880c7, BGMPB2020, BGAFF10OFF, bGhOnEy10, Email5, BGSS10%SW, Eachine11, bgshOOp10, BGRC902, BG11EACHINE, BGEachine2021, BGCuponation10
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for Eachine M80S Quadcopter Three Batteries. The lowest price was: $44.84.
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)).