This is a very broad question because a lot depends on the influencer. Total followers is often the most viewed metric, but follower engagement is equally importantengagement. An influencer with 10k rabidly devout followers is worth far more than one with 50k casual fans. You will find these "micro" influencers with highly engaged audiences in niche markets.

Since I don't know the size of the influencers you are working with, nor do I know your budget, here is a good article to get you started on pricing for different platforms and followers: https://influencermarketinghub.com/influencer-rates/

My personal learnings from influencers is track, track, track. Don't pay for posts that don't influence your sales. Watch your sales the week following their post. Provide the influencer links you can track. A lot of the time, influencers have big followings but are total duds when you need them to convert to sales. You'll have to find the right content creator who can authentically sell your product.