One of the main thing while setting up a VM is its size and cost. This article will help you to understand how to configure the VM size and the costs involved for the configurations.
If you have already created a VM then you can change the size from the management portal using the below option.
In the above case I have chosen the Size as D4_V2 which gives a 3.5GB Ram with 50GB HDD for a monthly bill of 119.78 USD. Similarly based on your production requirements you can choose to appropriate size.