Just check coupons out (with price alert and history). What is the best price?
for ES3 / ZST / ED12 / Low Battery Alarm / On-cord Control / English and Chinese Voice Prompt
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):
Price history and price alert
Here is price history (for all/most countries) for KZ Wireless Bluetooth Module Upgrade Detachable Wire.
Price records source(s): Gearbest
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)).