Garmin is offering low prices temporarily; I just got a GTX 335 for my Bell helicopter that slides into the old transponder panel space, is a complete ADS-B out/ transponder solution, and is under $3000 with WAAS antenna at most retailers (check Gulf Coast or Pacific Avionics, for example).
I paid for $2020 delivered for whole set (TT22 Transponder +TN72 GPS Source + TA50 GPS antenna) and $130 for AV-74 Blade antenna, total of $2150.
Requested from FAA an ADS-B report 2 days ago, everything works as it supposed to:
All of the above has concerned ADS-B out. As for in, there are several options and it depends a bit on what other stuff (displays) you have. I have a Garmin 660 as my primary/only display and added a Garmin GDL 50 to get ADS-B In. I went with the remote version for the gyro but in hindsight wish I had gone with the “basic”: smaller, less expensive, and in an open gyro the built-in antennas are fine. I went with the “basic” for my fixed-wing and just love it: I even dropped my XM weather subscription because the ADS-B weather is so good. And for the fixed-wing, the AHARS makes for a great backup AI for IFR flying. They were $100 off of the $100 off price at the end of the year, so I got it for $600.
For less, one could go with a Stratux for about $150, I think, and use Avare for free on an Android phone or tab. I still use that setup in my fixed wing as my primary for charts and plates.
ADS-B is such a great tool even for gyros