The Australian woman thought her timepiece's battery was dead but once she took it to a local store she found out the price of the repair was less than she expected.
She told Lotterywest officials: "I went to get the battery changed in my watch. It was cheaper than I thought, so I also got a scratchie.
"It was a spur of the moment decision and the best thing I ever did."
She'll be using the money to pay off her house and look after her children, but she'll be sticking with her repaired watch.