If you have a full bowl, try holding the handle down until the tank empties. Usually it will shut off with water still in the tank. It's not a fix but it will help while you're contemplating what to buy.

Or, if the sink is upstream of the toilet, you can turn on the water to get more water washing down the pipe to help move things along.

“In a time of deceit telling the truth is a revolutionary act.”
― George Orwell

It's not over when you lose. It's over when you quit.