Basically copy coupon, view price history or create e-mail price alert. Do you want to know what the best price is?
Maximum Discharge Power: internal 40W/500W(external discharge and recover discharge), Equipment Weight: 250g., Appearance dimension of equipment: 97.5X64.5X40mm, Maximum Charging Power: 500W, Maximum balance current/number of battery strings: 2a/6S, Input voltage range: 9-40VDC, Maximum Charging Discharging DC power supply current: 20A, Battery Type: LiHV/LiPO/Li-ion/LiFe/LTO/NiZn/NiMH/NiCd/Pb
Aliexpress
I could not find it 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. There is one coupon available! Pretty cool, huh?
Link: Banggood product page
1. ($70.12): BGGAL8
coupon code has to be applied in shop’s 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): 7d18f7, BGAFF10OFF, BGCuponation10, BGBCSpring1, BGDAVIS, BGHONEY2110, Parts8, BGRCBC11
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Here is price history (for all/most countries) for PWMWAVE B52 500W 20A DC RC Battery Balance Charger.
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)).