How to set up DEV/QA and Production to avoid paying for duplicate records

What’s the best way to set up indices so that one can separate DEV/QA from Production?

The amount of records one has can dramatically affect the price one pays. I wonder if having separate indices for DEV/QA and Production makes sense even if they contain somewhat identical records? I presume it would allow one to test Algolia configurations, data input and output without having to fear for mishaps.