This is very good practical information before you think to go for Public Cloud VM's.
It is also good to know that Cloud vendor prices can go down upto 50% or more when you are actually ready to enter the contract.
Do we need to consider other factors like
-Network bandwidth required
-Network latency between Client Machine and Cloud VM on which Server Application is running
-Discount you get on Power Consumption if your utilisation (Transactions) is minimum or nill except peak hours etc.
-How Cloud Services provider acts if you want to migrate to new Service provider
-How Cloud Service provider handles when you want to discard VMs at the end of the Contract