Preview book data on an Amazon search like BSR, royalties per book with estimated daily and monthly sales and profits.
This doesn't make me feel confident; I've noticed that in my KDP listing using the KDP extension it says that I am making $2.75 per book sale when in fact my royalty is just $1.61. Why such a big discrepancy? Makes it difficult to gauge how well others are doing using the same method (unless you just agree to knock a third off the shown royalty)
https://www.sellerapp.com
KDPMiner
https://selfpublishingtitans.com
https://selfpublishingtitans.com/
https://kindle-prime.com
https://www.myseobots.com
https://kdpuploader.com
Productor Apps
https://copytasker.com
Digital RaiHan
https://bookbolt.io
https://bookbeam.io