I created a VPC and a RT and a NACL too got created along with it?
I don't plan to use the VPC immediately but it will help me if its there for doing some study prior to creating further resources in it.
Does the current state of the VPC cost me anything. Should I delete it and recreate it when required for cost reasons?
The resources you mentioned specifically are free within a VPC (in fact AWS spawns a default VPC in each region within your AWS account).
There are however, a number of other VPC resources which do have a financial cost to launching them such as NATs and VPNs. For more information take a look at the Amazon VPC pricing page.