Are unbooted linodes billed?

You mean after you sign up for a Linode VPS, and it's resources are dedicated to your setup, and you and only you have the password to access it's management console - that if you decide not to place YOUR VPS online they charge you - well that's just crazy talk (I mean common sense).

/me builds a t(r)oll-free bridge next to vonskippy's.

Also, yes. You pay for the (virtual) machine. Is it running or not, doesn't matter. On the other hand, if you need one only for a few days a month, consider creating it only then and deleting afterwards. You are charged for a month up front, but if you cancel a node before that month passes, remaining time ends up as account credit, and is used to pay your next bill (or part of it).

Creating and deleting a node, (and, probably, copying a disk image from another one, if you don't want to rebuild the OS each time) surely can be automated via Linode API.

Rent an apartment somewhere, don't move in, and see if you get billed 8)

I think Linode operates on a similar principle. The resources are being reserved for you, whether you use it or not.

EC2 is a different story… If your usage pattern fits EC2 better, maybe Linode is not the best solution for you. But most of us are fine with long-running Linodes… :D

Does this mean that if I have a balance that exceeds the monthly cost, say $40 and I bring up a VM the cost of the time used will come out of the $40 rather than have my credit card billed for that one?

@rsk:

/me builds a t(r)oll-free bridge next to vonskippy's.

Also, yes. You pay for the (virtual) machine. Is it running or not, doesn't matter. On the other hand, if you need one only for a few days a month, consider creating it only then and deleting afterwards. You are charged for a month up front, but if you cancel a node before that month passes, remaining time ends up as account credit, and is used to pay your next bill (or part of it).

Creating and deleting a node, (and, probably, copying a disk image from another one, if you don't want to rebuild the OS each time) surely can be automated via Linode API.

yep