Funny you should ask that question. After determining the transponder/ADS-b out-in and whatever else it takes to "see" was too expensive I looked in the the "be seen" part of the saying.
And I just returned from my local bike shop with a Bontrager Flare RT Tail light with remote control in my possession. It was not cheap, at $80 but is very bright, small and rechargeable. They claim a 2k range in daylight. The remote control was $70 and I could have done without it. All I have to do is figure out where to mount it, yea, I know cant put anything on the aircraft as per the FAR's, but maybe near the wheel well facing rearward? Also, I checked into DOT tape truckers are required to have all over their trucks. Again not cheap at $30 per 25'x1" roll, but very bright in the daylight sun. Maybe the underside of the fuselage for this tape? And lastly if I really want to be seen, I might have the auto body shop near me paint a hunter orange stripe (12'x1.5') on the underside of my wings. I have a few quotes of $500-$650. Not sure about this one, I'll have to think about it, since my wings are carbon, painting them is no big deal.
Thank God for the off season so we can get stuff like this done.
Cheers.