The tritium is bred from lithium, so essentially free.
That has to be the biggest hand wave I have ever seen in my entire life.
I'd just point out a couple of obvious things. First off, the lithium you breed tritium from is very much not free, and since there are different reactions for Lithium-6 and Lithium-7 (both produce Tritium, but the Lithium-7 reaction doesn't consume the neutron, which is probably very important) you probably need to enrich the Lithium somewhat -- which is again very much not free. For all of the hoopla about fusion it doesn't seem like many people are looking at the engineering problems required to build a practical Tritium breeding system.
The other obvious thing is that getting all of the Tritium out of a hunk of Lithium is probably going to be at least a little bit challenging, given that both elements are wickedly reactive and there is the obvious engineering challenge of how much of your Lithium you let react before you extract the Tritium -- obviously you can't go for one hundred percent conversion because the Tritium would just float away, or more likely catch fire.
So no, not "essentially free".