Cable Length (m): 0.55m, Driver unit: 8.6mm, Frequency response: 20-20000Hz, Impedance: 16ohms.
Check coupons or create price alert down below. You probably want to know what is the 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 Hong Kong.
Link: Banggood product page
1. ($15.39): BGEP51AA
2. ($17.15): BGEP51
3. ($19.79): AFfbG10
4. ($19.79): affbg10
5. ($20.45): aff7off
just apply this code 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): e2bcea, TTxBG10, BG3CSUM, bgssaff9, BGTWS20, BGEP51A, BGEP51B, BGEP513C, BGplmeizu
(there’s a little possibility that old coupon will work)
Price history and price alert
Here is price history (for all/most countries) for MEIZU EP51 Earphones Red. The lowest price was: $14.29.
Price records source(s): Gearbest, 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)).