If you are not aware yet or forgot... craigslist is still one of best places to get free high quality leads and make money on them. It ranks #11 in US and #73 worldwide.
Besides the job section where you can post working URL links you can also use links in "Community" categories such as Classes, Events, General, etc. If you are offering free online webinars, online tutorials, etc...this is a good place to start. Not only start but continue building your list and profiting. You just have to be a little creative, create a good landing page (lead capture page), and create something valuable that you can give for free and also have some kind of upgrade. I hire people on fiverr to post ads for me because it works over and over again. One of my best campaigns generated 308 free leads and made 42 sales ($99 item) just from 1 Event post in NYC on how to start an online business. It was 60 minutes free automated webinar on what is a website, how to set it up, how internet marketing works and how people make money as an affiliate...and then I sold a guide for $99 on advance internet marketing strategies. Not every campaign generates 308 leads but every single campaign has generated free leads.