Justifying the cost of influencer discovery tools to clients can be achieved by highlighting four key points:

1. Efficiency: These tools significantly decrease the time taken for manually searching, vetting, and reaching out to potential influencers. This translates into substantial time saved and increased productivity for agencies, thus justifying the cost.

2. Precision: The use of advanced algorithmic methods by platforms such as Flinque allows for a highly targeted influencer search, ensuring a better fit for specific brand needs and yielding better campaign results.

3. Transparency: Tools provide comprehensive analytics and metrics. This allows brands to track campaign performance, understand their ROI, and gain valuable insights into audience engagement. This level of transparency and metrics-based insights is a strong value proposition.

4. Scale: Influencer discovery tools enable access to a vast and diverse set of influencers across various niches and platforms. Manual discovery of such diverse influencers would be incredibly challenging and time-consuming.

While the cost of these platforms is a consideration, the value they bring in terms of streamlining workflows, ensuring a good influencer-brand fit, and providing comprehensive analytic capabilities can be a strong justification. As always, the specific needs and resources of the team should guide the decision.