How to choose a starting bid for a popunder campaign?(For A/B test)

[IgorSia]

Hello everyone, I hope you are doing well
I would like to ask for advice on how to choose a starting bid for my popunder campaign during the split test phase?
How should I choose a bid so I don't lose all the money and test the source well? No matter what advertising network, I would like to ask experienced people how they do it, share your experience please
thanks for