well, getting visitors to your site is the biggest problem for all website owners. There are two ways to drive traffic. First is naturally through search engines or other sites with traffic coming for free. This can only happen when you have extensive SEO done on your site with loads of hardwork in the right direction. Second method is by using promotion services like adwords where you might want to spend some money. But as you said, you don't want to spend money, hence the first option is good for you.
And for that, you got to do a lot of hardwork before you can even see few visitors coming in.
hope this helps.