I agree that it’s probably not a big amount. But note that it can be potentially quiet a bit more than the 90$. Task runtimes are always rounded up to the nearest minute.
For example, in our pipeline we have 5 different linter tasks (for different subprojects), running each only a few seconds. Nonetheless, we’ll get billed for 5 minutes on every commit.
Ah I see, they are not minutes as on the clock. They are runtime minutes. That changes my assessment. I was thinking that they picked a balanced price point not to scare away many people except probably personal projects or unfunded open source. If it's something potentially in the ballpark of $500 per month it's a bit too greedy. It's more like: we want only corporate customers, free tier users need not apply.