because you are reducing the pool of people who will talk to you. I think I would rather find out about more opportunities in total. A good way to save time is only deal with recruiters who will mostly converse by email and send through a job spec.

The one benefit we did not anticipate was the "honesty". A lot of recruiters will say "oh, we don't have pay bracket info"... yet as soon as $100 is on the line, we find out that it's "here's the pay bracket info just so we don't waste each other's time". Honestly, if I told you to ask for $100 upfront in order to get the full job details from someone, you would think I'm pranking you.

Edit: On the "who will mostly converse by email and send through a job spec.", we also found a lot of recruiters will downgrade from "it's a quick call" to "here's an email" as soon as that "quick call" is a "quick paid call"