Greetings!

You can restore a backup at any time, at no cost. You can also convert a backup to a snapshot and use it to create a new droplet. A snapshot is billed at $0.05 per month, per GB (size of snapshot). The cost of the droplet you create from the snapshot is the hourly cost of that droplet size. If your hourly costs rise up to the monthly cost, just like your other droplet, it halts the hourly cost and sits at the monthly rate. So, for example, a $5/m droplet is $0.007 per hour, and that has a cap at $5.

Hope that helps!

Jarland