This is the best price I could find.
https://www.arrow.com/en/products/antusb-m/dynastream-innovations/
Whoah! Nice find!
I picked up some no name ones off of EBay for $8.00 a piece. They have 3 frequencies and 8 channels according to my Ant+ software.
They were here stateside too. Most of them are shipped out of china.