That is not a question that can be answered in a forum - you would be much better off talking to your licensing representative. There are most likely options that your reseller and/or licensing agent can provide that we would have no idea are available.
The prices can be different - depending on software assurance and other considerations.
It also will depend on usage and whether you really need core licensing or something else. Check with your licensing representative or reseller - they will have the best information available for you.