I looked at the directories which I think you are contemplating a while back and they generally offer these options:
1) Free listing: You have to wait to be approved, and it could take several moths to be approved.
2) Free Listing With Reciprocal Link: You get a free listing in a shorter period of time (say a week or two instead of waiting several months), but you need to provide a reciprocal link back.
3) Featured Listing: You pay a fee and you get a link right away, and it is generally placed above the other listings (i.e., the Free and Reciprocal link listings).
My opinion: Don't bother submitting to these directories at all. These are general SEO directories, and they are not going to influence your rankings. Worst case, they could hurt them. (See threads on over optimization penalties.)
The people who have these types of directories usually have 50 or 100 or a whole ton of other directories in all sorts of different niches. They spend almost no time curating these directories, and they are filled with links to bad sites (or link to sites that no longer exist).
Most directories that have an active review process charge money for the review.
dvduval is talking about a different type of directory; one that is run professionally. They might have some SEO benefit, but people still debate that as well. Most people agree that being listed in your local chamber of commerce directory is beneficial to SEO, and you have to pay to get in it - so there you have a "paid" link that isn't penalized by google.
Here's the bottom line: If you get a link that your competitor(s) can get just as easily (i.e., paying the same amount of money), how good of a link could it really be?
I think the links that matter are the ones that your competitors CAN'T get.