“Between killing and dying there's a third way: live”

Source: The Drawing of the Three

Source: Even Cowgirls Get the Blues

Source: Revolver

Variant: Mostly I just kill time," he said, "and it dies hard.
Source: The Long Goodbye

Attributed in Naomi Klein's No Logo: No Space, No Choice, No Jobs https://books.google.com/books?id=Yq_WAUXqRAEC&pg=PA325 (2009), p.325, and in Mark Lynas' Seeds of Science: Why We Got It So Wrong On GMOs https://books.google.com/books?id=V10-DwAAQBAJ&pg=PA16 (2018), p. 16.
Attributed

"The West Should Fear the Growth of State Capitalism," http://www.telegraph.co.uk/finance/economics/7883061/The-West-should-fear-the-growth-of-state-capitalism-Ian-Bremmer.html The Daily Telegraph (July 10, 2010).

Widely attributed to Camus on the internet, the earliest attribution of such a statement to him yet located is an unsourced citation in Quotations from the Wayside (1999) by Brenda Wong: "Many things are worth dying for, but none worth killing for." The earliest occurrence yet located of such a statement, by anyone, is one by Albert Dietrich in a 31 January 1943 letter to his conscientious objector status Hearing Officer, reported in Army GI, Pacifist CO : The World War II Letters of Frank and Albert Dietrich (2005) https://books.google.co.uk/books?id=3o4JN_C69VwC edited by Scott H. Bennett: "There are perhaps many causes worth dying for, but to me, certainly, there are none worth killing for."
Prior to the attribution to Camus, the most widely publicized occurrence of such an expression was probably in the song "Too Long A Soldier" https://www.youtube.com/watch?v=YoQcU1ecPOc by Neil Giraldo and Myron Grombacher, sung by Pat Benatar on her album Wide Awake In Dreamland (1988): "I've seen so much worth dying for, so little worth killing over."
Misattributed

“Poetry in War and Peace”, p. 129
Kipling, Auden & Co: Essays and Reviews 1935-1964 (1980)