There are some cities need to pay for posting. This is near about 160 cities along with their sub cities in total over 240 cities that you have to pay $15 -$75 to post an ad in Jobs section.
I will give you a free cities list (270) along with the paid city list to start your job posting campaign.
10 minutes FREE tips and consulting for Craigslist posting. Free cities list + Paid city list
I am sure it will help you to save near about 6 hours.