Basically copy coupon, view price history or create e-mail price alert. Let’s see what best price is ATM.
Standby time: 15 days, Battery Capacity: 100mAh, Charging Time: About 2hours
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 Hong Kong.
Link: Banggood product page
1. ($10.99): BGe487cd
2. ($24.97): band10
3. ($24.97): BGWRIBAND10
you should apply the coupon in your cart after clicking “Proceed to checkout”. Click to copy code and open shop.
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): PCnetWork, 42hb, 35honor, 38hb, 15wt, 35ho, honor15, H4pat28, 502C6B, honor36, honor35, Dhonor4, honor4DL, unaxhw4, 33band4, TTxBG10, hwband4, BGHwband4, 646f09, BGhonor4, BG3CSUM, BGDealspotr0708, BGUK15, BGHWhonor4, AFfbG10, BG32Honor4, BGbuywithus252, BG22Honor4, BGBFAFF2019, BGHONOR20, BGHonor429, BGVDay10%off, BGwkband4, BGBGAFF10OFF, BGSS10%SW, bgshOOp10, BG11SHOP, BGHON4, BGNWHON4, BG3HON4, BGHNO4, BGHU0538, BG0c1cdb, BGbf11dd
(probably won’t work, but you can try them out)
Other warehouses/versions
This item is available in 1 another warehouse/version!
1. Hong Kong – HUAWEI Honor Band 4 Bracelet Black ($-3)
Price history and price alert
Do you need price history chart (for all/most countries) for HUAWEI Honor Band 4 Marble Blue? There we go.
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)).