See: https://www.newegg.com/polycom-2200-4952-001-accessories/p/N82E16833617015 (https://www.newegg.com/polycom-2200-4952-001-accessories/p/N82E16833617015)
You must subscribe to their email list to be eligible, and don't forget to add the coupon number.
FYI: $49.99 Obihai OBi200 1-Port VoIP Adapter with Google Voice
In Stock (on 11/9/2020)
Ships from Amazon
Sold by Obihai Technology, Inc.
https://www.amazon.com/gp/product/B07FCS1NGM/ref=as_li_qf_sp_asin_il?ie=UTF8&camp=1789&creative=9325&creativeASIN=B07FCS1NGM&linkCode=as2&tag=obihatechn-20