Go down and check coupons out. Remember to check price history if it is available. What is the best price?
2x Soocas Original Dupont Bristles Electric Toothbrush Head
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 code price check (UTC time):
Banggood
Banggood warehouse is located in China. I have no active coupons for you right now.
Link: Banggood product page
Price: $-3
It looks like this item is out of stock in Banggood. If you found it then please send me the link. I will replace it.
Click here to search on Banggood!
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): ML15%Pro, BG15%SP, 9431a8, BGEX3R0, BGEX3R83, vipupgrade8, BGHU356, BGWHITEREPLACE, BGSOOCASSEP, BGNOV7, BG11VIPD, BGBFHC4, BGSCTF1, BGSOOCAS18, BGTMCB7, BGHU841, BGXIAOMI811, BG11025, BGAFF10OFF, BG11716, BGHUD412, BgcLuBofErtA10, BGCC0704, BGHBHJ104, BGCuponation10, BG10OFFAFF, BGAHM34933, 13f142, BG10OFFAFF1, BGdb168d, BANGGOODSD, BGHealth06, BG4ee866
(you can check these old coupons out, but these probably won’t work)
Price history and price alert
Price history (for all/most countries) for Xiaomi SO WHITE EX3 Toothbrush Replacement Heads 2Pcs is here.
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)).