vagrant

# Vagrant Documentation
# @see http://docs.vagrantup.com/v2/cli/package.html
# @see http://stackoverflow.com/questions/19094024/is-there-any-way-to-clone-a-vagrant-box-that-is-already-installed

# <command-1>
vagrant package --base <virtual-box-name-or-uuid> ^
                --output </path/to/package-name.box:package.box>

# <command-2>
vagrant box add --name <box-name> ^
                --provider virtualbox ^
                </path/to/package.box>

# <command-3>
vagrant box list

# <command-4>
vagrant init

##########################################
# Create a new box from your existing vm #
##########################################

# cd into the directory with your Vagrant file

run "<command-1>"
This will export box to a file (package.box is default box name).

run "<command-2>" to add package.box to your existing boxes.
Assuming you are using VirtualBox and not VMWare.

run "<command-3>" to verify it was added.

# Now you can just create a new folder, run "<command-4>" as normal and set your box to the following:

config.vm.box = "box-name"

# The new VM will spin up with the exact data that was present in the previous VM.

:-)