Sleeves out of my vest
Giving a concession that sounds like something significant and is likely to get accepted as such, but in reality you've given away nothing of value, or something that you would have had to include anyway.
Bill: I gave that treadmill to the guy that bought my car to get him to say yes.
Bob: But you were already planning to give that to charity.
Bill: Exactly. I gave him the sleeves out of my vest.
Bob: But you were already planning to give that to charity.
Bill: Exactly. I gave him the sleeves out of my vest.