You can still offer a "free tier for existing customers" and call it "development" or something. This lets people who are already known/paying to spin up test instances, without having to go through purchasing, which leads eventually to more paid usage.
I guess it depends on where you think the platform is going, and which segment of the market you think the revenue is going to come from. I'm just saying: it's a significant cost. It's maybe the most important thing to know about the hosting business.
