In the previous instalment of my $100 Drupal site series I covered resources and infrastructure. In this post I will be covering the development tools I think you need in order to build and sell Drupal sites at the $100 price point. Given that Drupal 7 is close to release, it is assumed that the sites will be built using D7. I don’t believe that it is smart to invest heavily in Drupal 6 for new long term projects, given D8 could be out in 18 months and D6 would then be unsupported.