Don't pay for any directory - get yourself to the top of google
Unless you have 30k per month to keep on googles first page, then forget that dreamland idea. I know of one SEO who charges 8k per client, so that's probabaly minimum spend you're looking at. Then you got maintenance fees on top, so yep - tens of thousands a year - so not workable for many I'm, afraid.
Much guesswork involved with any website, and seems to me that this applies to blogs, forums ie; traffic is never disclosed, just 'member numbers' which don't tell you squat about 'activity' on a website. Some may show you who their clients are eg: BMW, BBC etc but traffic levels are a secret, youll never get to the truth of how well or poorly directories perform.
You can have 1000 members doing 10000 searches, buying 200k of products each year. Its always about quality than quantity. Directories always seem to get a battering, and much is misguided info by fools who advise fools, who have never owned, ran, worked for etc any directory at all. So how can they know about any directory's numbers? - hello, do you see what I'm saying here.
But any directory needs investment, although can be done using the
lean and mean method - but at somepoint needs capital to get it started. You see - many have set up directories this, so problem is the 'directory' got tagged with a bad rep, and now the only advice or bad mouthing comes from forums, which I distrust to a point anyway as I've done most promotion activities so know what works and why.
Ive always viewed directories as 'easy link' in that their cheap, few barriers to entry and you get a good long term before renewal is up.