We’re not going to lower the minimum prepaid amount.
It’s difficult to have burst usage that grows unexpectedly on Fly.io. With the exception of bandwidth, everything we bill for requires manual provisioning.
We’re comfortable with this setup, and think it’s a good balance between helping you manage your costs and the level of engineering effort on our end. In general, we’re not going to put a lot of time into preventing you from provisioning paid resources. We’d much prefer to refund mistakes after the fact.