How much you invested on promoting your web/bid directory ? And what kind of promotion will you recomend ? AdWords ? submitting to quality directories ? banner ads ? How much you need to invest in a directory ? This question might sound strange because I know that you need to work hard every day as much as you can to promote it...but as for begining ? what did you do first when you had a PR 0 directori with few pages indexed and not so much traffic ? What were you're first stepts in this business ? ( if I can ask )
for zorg links I sponsored loads of themes bought high PR links (bad) submitted to loads of paid web directories, whatever the price/PR of them. ordered around 1000 manual submissions ordered some social bookmark submissions bought banner ads on as many places i could bought blog posts/reviews on many quality webmaster blogs spent serious cash bidding high on other bid directories spent a lot of money on DP sig links
I have to date spent anywhere between $100 - $500 per month for WP theme sponsorship and submission to web directories. My suggestion is that you sponsor some WP themes and submit to free and paid directories. They are the most effective advertising and works well for me.
$2000 seems to be a good marketing investment in order to start braking even after first 6 months. Notice I underlined marketing, marketing doesn't involve development and maintenance costs.