Thanks to B at In The Middle of the Right for the link
"The president’s second fascinating gloss on the concept of rights has to do with negative and positive rights. In the U.S., when we think of rights, we think mainly of negative rights: rights against the government. The Bill of Rights is largely a list of things the government may not do to you. It may not prevent you from having your say, or praying to your own God, or living unbothered in your own house. It may not discriminate against you on account of race, religion, and so on. But it has no positive duty to feed or house you."
The simple summation of Negative Rights don't cost money, but Positive Rights do, I think is spot on.