One of the approved units is the FreeFlight Systems 1201. It is posted here for less than $3000.00. However, it is only sold "installed" so additional expense.

http://sarasotaavionics.com/avionics/1201

Probably should run everything - -(what it's connected to, intended use,and installer)- - by your FAA FSDO before spending any $$$$.$$. Go back up and read Darrly Ramm's Nov.13 post which says "FAA has made it clear that FSDOs are forbidden from issuing any field/337 approvals for any ADS-B data-out installs".

Beats me.