The socialite revealed the purchase during a joint interview with her sister Kourtney on Piers Morgan Tonight.
When Morgan asked the pair what the most expensive thing that either of them had purchased was, referring to her sibling, Kourtney said: "Probably a watch for yourself."
Kim then commented: "It was a watch that was $115,000. But I got a really good deal and I traded two in for it. So technically I was out of pocket about $50,000 (£31,400) or $60,000 (£37,700). I don't think I could ever go and just spend that much."
However, Kourtney insisted that she is not in the same financial position as Kim and that her main concern is providing for her 13-month-old son Mason.
Piers asked the sisters: "Did you ever think you'd be in a position to spend $115,000 on a watch?"
Kourtney replied: "I don't do that stuff for myself. I just think that... I don't have as much money as Kim and I have a baby and I'm thinking about college and expenses."
Piers Morgan Tonight airs on weeknights at 9pm ET on CNN in the US and at 8pm on CNN International in the UK.
