The short version is it seems like a big "gotcha" that there is no way to limit bandwidth or spending on that or other resources ahead of time, and that might be a deliberate business model that is more aimed at well-funded startups or large companies that are monitoring costs much less closely than an individual or small business.

It's not necessarily too hard to just not dynamically spawn a bunch of machines, but the bandwidth one is going to sneak up on people.