What do you think how much is worth one link in a free directory if you want to hire someone to submit your site for you?
I don't judge people on a per link price basis. I judge them by conversation and trial. If they do good, up goes the subscription. If they don't do good, I just won't use them again. I appreciate other peoples hard work.
Submitters can have astonishingly different acceptance rates. To an extent, it depends on the quality of the site they are submitting: anyone who can get a good acceptance rate for a MFA is working something of a miracle, for example. But it's mainly to do with how well the description is written, and whether or not the submission meets the criteria of each directory. It can be hard to track acceptance/rejection rates precisely, because you don't always get an email from each directory. But you can look at the emails you do get back 2 weeks later. If less than 50% let you in, something is probably wrong.
Ask for the category links where they submitted, a month after check all the categories and see if your links is there, figure out the acceptance rate then
I say ask for the entire list prior to using them too A lot of people use practically the same lists, unless they have their own little network.
I think price depends upon theme of your site and category where you are submitting and the PageRank of that category. We buy directory category listing on various factors not just the one