Just check coupons out (with price alert and history). What is best price?
BlitzWolf® BW-SX31 3 in 1 Wireless Lavalier Microphone iOS Type-C 3.5mm Jack Mic DSP Intelligent Nosie Reduction Low Latency HD Microphone for Phone Camera SLR PC Laptop – Two Microphone
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. I am tired of searching coupons, but I found one for you…
Link: Banggood product page
1. ($16.99): BGRJU6SX31
put item in your cart and apply coupon code there 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
There were country-specific coupon codes published on Couponsfromchina social channels and price alerts. Coupon price may vary by country, because there’re different VAT rates, shipping cost etc. There is a chance that some latest coupons are still working:
1. (1.8.2024, $15.99): BGcd156a
Item: BlitzWolf BW-SX31 3 in 1 Wireless Lavalier Microphone 2pcs
Countries: CzechRepublic, Hungary, Poland, Slovakia(SlovakRepublic), Slovenia
2. (31.7.2024, $15.99): RendKinai867
Item: BlitzWolf BW-SX31 3 in 1 Wireless Lavalier Microphone 2pcs
Countries: Hungary
3. (30.7.2024, $15.99): BGRJU7BSX31
Item: BlitzWolf BW-SX31 3 in 1 Wireless Lavalier Microphone 2pcs
Countries: Greece, Portugal, Spain
4. (1.5.2024, $19.99): BGRMAYSX31
Item: BlitzWolf BW-SX31 3 in 1 Wireless Lavalier Microphone 2pcs
Countries: CzechRepublic, Greece, Hungary, Poland, Slovakia(SlovakRepublic), Slovenia
Old coupons (from the oldest to the newest): BG8d4433, BGAudio9, BG43e58f, BG0da0c7, BGAnniv83
(sometimes old coupons work, so you can check them out (this site checks them on every price update))
Price history and price alert
Here is price history (for all/most countries) for BlitzWolf BW-SX31 3 in 1 Wireless Lavalier Microphone 2pcs.
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)).