I have just checked coupons. The lowest price I could get is $16.99 for TRX30 Bluetooth 5.2 Transceiver Audio Transmitter Receiver (in Banggood). Check coupons or create price alert down below. What is the best price?
Transmission Rate: 50 (Mbps), Distance(L.O.S): 20m, bluetooth version: 5.2+EDR, Size: 49x49x14mm, Material: ABS, Model: TRX30, Effective Working Distance: 10 (m), Color: Black, Whether it is plug and play: Plug and Play
Latest price update (UTC time):
Banggood ($16.99)
Banggood warehouse is located in China. There are no coupons for this product in Banggood. Is it a reasonable price for this item? Hmmm, price is higher than average (which is $10.32 right now), so better set price alert down below…
Link: Banggood product page
Price: $16.99
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k and https://couponsfromchina.com/short/5cd
Old coupons (from the oldest to the newest): BG68b0f4, BG589b2e
(system checks these coupons on every price check (like once per 24 hours), but you can check them out anyway)
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for TRX30 Bluetooth 5.2 Transceiver Audio Transmitter Receiver.
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)).