So chatting with someone yesterday as they figure out their own products and services they had a whole heap of things "bundled" into a paid for product. They were saying that a certain element of that bundle was free but it was important to pick them up on the fact that it was not free it was included.
Free might apply for something you literally give someone... pretty much anything that is free is a sales tool, or potentially a research tool. If something is included in a "money maker" product or service it's actually included so don't mess that up. Work out what the value is of the "free thing" either by your&their gut or but time and cost, probably a combination of both and all to come to some conclusion.
I guess the point is that if you are trying to sort out your products and services so you have confidence in them don't allow people to make this mistake.