As a seasoned web developer, I can tell you that if you want to promote your brand on the web, there are really only two effective ways to do it... Social Media, or your own website. The first is free, and the latter involves money to host, and expertise to implement.
There is no shortage of reasons why major companies have big presences on Facebook, Twitter, and Google +... even though they have plenty of resources for hosting their own site. But even social media is not without what I would consider to be a significant investment (your time).
No matter how you go, you will need to invest time in promoting your site, and adding content that, simply put, gives people a reason to want visit your entity in the first place, and to return to it regularly. If your not willing to do that, just walk away. Just throwing something up someplace and leaving it there in the hopes many will discover you is simply a waste of time.
But if you have the time and energy, social media, as many have mentioned above, is the way to get started. It is something you can grow at your own pace, and to test the waters so to speak. It is a timely way to add content and to interact with your customers and prospective customers. And after a modicum of success, you can always put up a site later and crosslink to/from the existing presence you have built.
HTH