Make it clear WHY some balance is required to start a compute server

[novoselt]

At the moment users are rightfully confused:

"I have $2.36 in my balance and when I try to start the server named "Cheap Test Server" which costs $0.02/hour of operation, I get an error that states "You do not have enough credits to spend up to $2.50 since your balance is $2.36, and this would cause your balance to go below your allowed minimum of $0.00. Please add at least $2.50 to your account. There is a minimum payment of $2.50."

The error message should state exactly the balance required to start the server. Is it a flat amount? does it depend on the server configuration? I think it should cover at least one hour of run-time and perhaps some network traffic. I think it also should give some sense of why it is required.

Something like: Your balance of $2.36 is not sufficient to start this server. You need to have at least $3.02 to cover the cost of running the server for 1 hour as well as 20GB of outgoing network traffic.

Regarding the flat component, however, I think it should be substantially less than the minimum transaction, so that those who added the minimum amount possible can experiment with compute servers. With 1 hour and 10GB it would be $1.52.