Influencer marketing, especially long-term programs, need a strategic approach to enhance the ROI by reducing the Cost Per Mille (CPM). Here are a few strategies to balance cost and quality:

1. Long-Term Relationships: Brands should aim for a long-term association with influencers. It fosters trust and authenticity which can improve audience engagement and lower CPM. Platforms like Flinque can help in maintaining deeper partnerships.

2. Micro-Influencers: Engage with micro-influencers who have a specific follower base that aligns with your demographics. Their rates are often lower, reducing CPM, and the audience is highly targeted.

3. Performance Analysis: Regularly measure the campaign’s performance, using tools like those provided by Flinque for insights on audience behavior. This helps in making informed decisions and tweaking campaigns, hence reducing CPM.

4. User-Generated Content: Encourage influencers to share user-generated content, which is typically cost-effective and authentic, hence potentially lowering your CPM.

5. Value Exchange: Instead of only monetary terms, find out what other values you can provide to influencers- product, exposure, etc. This can reduce the direct cost, hence CPM.

6. Platform Choice: Influencer marketing platforms like Flinque help streamline campaign management and provide insights into cost-effective options.

As a parting thought, successful long-term partnerships between brands and influencers hinge on shared value and ongoing cooperation. This can not only drive down CPM but also increase engagement and conversions. Remember, the cheapest option may not always provide the best value, and quality content should never be compromised.