Seller beware! Guerrilla marketing is innovative and seizes the moment. It is a controversial way of promoting your products and services. The idea is that in some way you ambush your customers or the media that they are exposed to, such as TV or radio. For a small business, your resources will be limited; an example would be that a celebrity or sports person visits your town or a trade show organized by your industry association. You could wear a T shirt or display a banner with details of your business upon it.
If you are more dedicated, you could project a picture of your product or logo on to the walls of a local high profile building. You could take pictures of it, and share it on social media. Check your local laws and regulations. Remember, you need to be a responsible organisation because that is the least that your customers will expect.