Agreed, "free" is too broad.

I was responding to parent's question though: "Can you call it open source if you need a subscription license to run / edit the code?"

I'd say no. If you have the code in front of you, it shouldn't require a license to run. Even if the whole point of the open source software is to interact with a proprietary piece of software or service, you could still run it for free, it probably just wouldn't have much utility.