Calculating marketing ROI is a tricky task, but in general the consensus is that an inbound marketing agency (especially one specializing in a niche like SaaS marketing) comes with great advantages and rewards for your marketing budget. While paid ads online might be useful in the short-term, most SaaS marketing agencies will involve 'evergreen keywords' in their marketing strategy- meaning that they can create content that continues to draw in leads for years after it goes live.