How much RAM should I give ???
If I have Window 7 & 4GB RAM in my PC and I want to run Linux on VirtualBox, how much RAM should I give to VM ?
it depends on what you want to do in the VM, in your case 1GB + swap would be fine, but it depends, 4GB of ram is limited, phones nowadays have more Ram.
2 gb for general use. 4 gb for professional use and 8gb for business use and 16gb for enterpror use.