Just a warning, if you get on to the free list at Vilesilencer, and then go paid, you will be booted off the list on the next update. Free directories will always get more traffic, and you can abuse that to help you gain a few backlinks from circulating directory lists. However, with around 100 submissions a day on my free PR0 directory, the free option is very timeconsuming.
I agree, A dir should be free or paid, no in between or changing. Very few dirs have been successful doing this. The categories get filled up, why would someone pay to be on page 3 of a category when just a month ago someone got on page 1 for free. Either free or paid. If you are planning to make it paid, you should be strict on free submissions and only allow high quality sites. I wouldn't want to list my site next to SPAM
If you turn your directory paid,you'll get less traffic unless you promote it a lot! I will ,if the directory is promoted properly.
I think you are basing when you should go paid on the wrong factors. It should be when you are established enough, not by how many links you have in the directory.
Well a PR0 directory will eventually get some PR. It is just a matter of time. It's never too earl to get in. Note that as a directory gets a higher PR, the submission fee also increases. So the sonner you get in, the better it is for your pocket