Henry, three ways to what you are trying to accomplish:
1. Content marketing: Write detailed blog posts about your niche. Write them frequently. Buyers will read them and enter your sales funnel by their own volition.
2. Affiliate marketing: Use CPA (cost per action) model to acquire new customers. You are not paying for traffic -- only results.
3. Email marketing: Make sure people sign up to your mailing list and then send a monthly email that is choke-full of useful content. Over time, readers will associate your company with quality and will buy from you when the time comes. There is a book called DotCom Secrets which, despite its tacky name, has great content that is relevant to you. http://www.amazon.com/DotCom-Secrets-Underground-Playbook-Growing/dp/1630474770/ref=sr_1_1?ie=UTF8&qid=1454690278&sr=8-1&keywords=dot+com+secrets