Remarketing may be a solution for you. It is a method of PPC advertising that allows you to only advertise to those who have already visited a digital property of yours. This way, your advertising dollars are only spent on those who have shown an interest in your company/product/services. Remarketing is available via Google Adwords, Facebook Ads, and other PPC advertising services.

Of course, you still need a method of getting traffic to the digital properties first, which could come from discovery and due diligence marketing channels.

We use this method with our own marketing, as well as our clients', as a method to shave costs and be smarter with ad budgets.