I was told that it's body + lens, or body + speedlite, or all three, for the free 2nd day shipping. I.E. if you buy a body and a lens hood or something, that doesn't count, but that's just what the rep I ordered from said.
Some people are reporting on Slick deals it's any accessory. Even something that's less then $2.
When I ordered, I had bought a lens so I couldn't confirm.