Video marketing - make a video talking about a typical problem your niche faces and post it on youtube. Choose the key words carefully. Make sure your phone # is in the video title.
Forum marketing - find forums which your target market is gathering on. Answer their questions. Develop a reputation. Have a signature or profile page that leads them to talking wtih you.
Linkedin/Facebook marketing - Get into groups your target market is in. Engage with them. Develop your rep as the expert.
Each of these costs your time, but you can generate leads and sales with them.
Assuming cheap means not $$$ but time. Here's the best ROI.
1. Content Marketing: Blogging & Video - The reason this ones the best is that it has a long lasting effect (SEO). You can build up a following of potential customers, and even if you pivot your product, the customers should stay the same - so you can re-direct them to the new product. It always continues to drive traffic after you stop blogging. If you through in some guest post on top of that - it can be quite effective (ex: KissMetrics blog, BufferApp blog, Hubspot, etc for great examples). Marian knows best http://clarity.fm/marianschembari
2. Press / Media. This is the second best but it's very much a hits thing (sometime it drives qualified traffic, some times it doesn't). The key is to start with smaller outlets, then work your way up to getting covered by NYT, CBC, etc. Ryan Holiday is the master at this: https://clarity.fm/ryanholiday?b=h
P.S. Those are the only 2 in my mind that are "cheap" although they do cost time (which is money $$ in my book). However, even better then both of those is a relentless focus on building a great product or service that people can't help but talk about. That's the cheapest in my opinion.
Cheap isn't what you should be going for. Marketing is an investment, not an expense.
You should be looking to increase your RETURN... not cut your costs. What is better: paying 10 dollars and getting back 100, or paying 5 and getting back nothing?
If this makes sense to you, feel free to set up a call.
I agree with Dan. I also think that in most situations it is better to try "cheap" methods first. You need to know what you are up against before you put your chips all in. Many times using cheaper or free methods of marketing can spark new ideas on how to tweak your products or services. I always say that if you are not walking on the edge then you are taking up too much space. However, I don't like the thought of walking tight ropes without nets either. This is especially true for your own self-esteem and keeping your support system (family, friends, and investors) on board and your momentum going forward.
The number one place you should start is with making your website full of interesting and useful content and using a physical address for Google and Yahoo places.
Assuming your website is not brand new, I would recommend first analyzing your existing analytics platform to identify what is currently working well, and what is no working in terms of driving qualified website visitors to your site. From there, you can follow the pareto rule of identifying the 20% of efforts that are driving 80% of results, and focus all future efforts around that 20%.
I've written about this much more in detail here: