What is a good affiliate fee?

As a business owner in the cryptocurrency and finance space, I often find myself wondering what constitutes a good affiliate fee. Should I offer a percentage of sales, a flat rate per lead, or perhaps a combination of both? What factors should I consider when determining the ideal affiliate fee structure for my business? Additionally, how can I ensure that my affiliate partners are motivated to promote my products or services, while still maintaining a profitable margin for myself? Ultimately, I'm seeking guidance on finding the right balance between incentivizing affiliates and protecting my own financial interests.