Technically it is free BUT you have to get an account that has that dlc..
All this does is it transfers the account with the dlc to your account's download history. If you do this, you'll have the dlc forever on your account and you can do this with as many friends as you want. Also, you need a second controller.
my friend tried this, not using this tutorial and he couldn't get it to work, so I don't know if it is still working or not, but I'm going to thank and rep, because its for xbox, this section has been a ghost section for too long.