Hmm that's tricky, you have to keep in mind that with $100 per year you're maybe limiting entry in markets with a lot of resources (e.g. IT professionals in India).

Maybe I'm wrong, dunno about price points, I do know I find it quite easy to support someone on Patreon with $5 per month if I find the content valuable. And this should not be viewed as more valuable, people are not constantly looking to switch jobs or take on more work, for many it would be pretty passive network (as is LinkedIn).