settle up (with one)
To pay the balance of what is owed to someone. You get our jackets while I go settle up with the bartender. Brian and I need to settle up for those plane tickets soon—I hate having debt hanging over me.
settle up with someone
to pay someone what one owes; to pay one one's share of something. I must settle up with Jim for the bike I bought for him. Bob paid the whole restaurant bill and we all settled up with him later.