Best CPC for Fiverr GIG promote?

[akhlakpranto]

Hello good people,

I got Fiverr promoted gig option 1 month before. I ran one gig for promoted campaign and set customized cap is 0.40. got some clicks but still not getting any inbox. 

 

Now my question is, what is the best practice to optimize or keep the promoted gigs CPC? 

 

Thank you