for two pins

(idiomatic) Readily, with only the slightest encouragement.

Example: 2009, H. DeVere Stacpoole, The Man Who Lost Himself, ISBN 1434452980, page 202:
  He doesn't, but he's a man with an eye in his head, and he knows what we are, a boneless lot without organization. I say it myself, I said it only last night in this here bar, and I say it again, for two pins I'd chuck my party. I would so.
2010, Mary Balogh, Seducing An Angel, ISBN 074811758X:
  For two pins he really would slap a glove in each of their faces.
2014, David Mitchell, The Bone Clocks, ISBN 9780340921609, page 4:
  But for two pins I'd hand in blank papers and tell school where to shove Pythagoras triangles and Lord of the Flies and their life cycles of worms.