I actually found a simple way to just use a network bridge to share the internet connection of eth0 with eth1. Since I already have an account with a vpn provider (IPVanish, they have a tier-1 network), all I had to do was figure out how to share internet between the two ethernet nics.
The steps below, are to share an internet connection and create a network bridge between two ethernet nics, and then connect to the vpn provider. You need two ethernet nics on a single pc, a server.ovpn file, and your vpn provider's username and password for the vpn connection.
Create the bridge.
brctl addbr br0
Bring both interfaces down, as you cannot have an ip address on the nics.
ifconfig eth0 0.0.0.0 down
ifconfig eth1 0.0.0.0 down
Add the nics to the bridge.
brctl addif br0 eth0
brctl addif br0 eth1
Bring the nics up without ip address.
ifconfig eth0 up
ifconfig eth1 up
Bring the bridge up
ifconfig br0 up
Give the bridge an ip address of your choosing (example uses 192.168.0.1).
ifconfig br0 192.168.0.1
Start the client connection to your vpn provider
openvpn --config /path/to/vpn/provider/server.ovpn
You will then be asked for your vpn provider's username and password.
The password will not echo, so do not be alarmed when you do not see anything appear. Type correctly and press enter.
Anything connected to eth1 will now be using the internet connection, as well as going through the vpn of eth0.
If your isp modem/router has a working dhcp server, anything you connect to eth1 that requests an ip address, such as a roku streaming media player, will automatically be allocated one. Do make sure, that the ip address you give to the br0 is on the same subnet as your dhcp server.
The bulk of the answer I found at this link. I posted it here so that it would be of help to anyone else who has been searching for a simple way to do this on linux.