I know that the Tattoo shop that I go to charges $35 for the daith piercing.

I had mine done in the UK £20.00 it helps if you get a reputable piercer regarding placement not too shallow as it needs to be pretty deep set. If you are on Facebook there is a really useful group https://www.facebook.com/groups/857198007712593/ Rivka Chavi is really informative too if you need any advice regarding placement or healing.

It didn't work for me unfortunately but looks pretty.

I only paid $20 for mine

Both mine were 75 dollars and that was with some ear saline solution.

I think it might depend on where you live. Mine cost $40.00 before the tip. I got a titanium earring due to metal allergy issues.