I've done a fair amount of searching and can't find a straight answer anywhere.
The free tiers on most of what I've tried are basically useless — you get just enough to see real people are there, then hit a wall the moment you try to message anyone.
I've tried a few different things already with mixed results. Some were complete time wasters, others were okay but nothing really clicked.
Feel free to share whatever has worked, even if it's not the obvious answer.