Discharge Plug: XT60, Discharge Rate: 150C, Dimensions: 78mmx 39mmx 42mm (Lx Wx H), Configuration: 6S1P / 22.2V / 6 Cells, Minimum Capacity: 1400mAh, Charge Plug: JST-XHR, Max Burst Discharge Rate: 260C, Net Weight(±20g): 222g.
Just check coupons out (with price alert and history). Let’s see what best price is ATM.
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.
Link: Banggood product page
1. ($49.72): BGToys8
2. ($49.72): BG8OFFCOUPON
3. ($49.72): TTBLACK5
apply code in your basket (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): Cuponation9, BGGutscheine
(these coupons are old, so probably won’t work)
Price history and price alert
Price history (for all/most countries) for Tattu R-Line Version 5.0 22.2V 1400mAh 150C 6S1P RC Battery XT60 is here. The lowest price was: $42.99.
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)).