You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Model: ST2, Whether with mic: Optional, Earphone type: In-ear, Brand: TRN, Frequency range: 20-20000Hz, Cable Lngth: 1.25m±5cm, Color: Black/Transparent, Interface: 3.5mm, Driver unit: 1DD+1BA driver unit, Earphone sensitivity: 107dB/mW, Whether with cable: Yes, Impedance: 22Ω, Whether can replacement cable: Yes, Earphone interface: 2Pin(QDC), Product Name: TRN ST2
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China. There is one great coupon!
Link: Banggood product page
1. ($19.54): BGAlerabatKL
apply code in your basket (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): BG651551, BGBRPL2, BGHOTSHOP15, BG53e9c8, BGAlerabat1
(these coupons are old, so probably won’t work)
Price history and price alert
Here is price history (for all/most countries) for TRN ST2 1DD 1BA Earbuds.
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)).