purchaseNode() Netscript Function
=================================

.. js:function:: purchaseNode()

    Purchases a new Hacknet Node. Returns a number with the index of the Hacknet Node.
    This index is equivalent to the number at the end of the Hacknet Node's name
    (e.g The Hacknet Node named 'hacknet-node-4' will have an index of 4).

    If the player cannot afford to purchase a new Hacknet Node then the function
    will return -1.