Supply and demand. She is popular and will go for a lot. But if she goes on a day when a lot of people have full towns or are sleeping you wont have as great of success. Oh the joys of retail
It all depends on wether there's someone else willing to bid higher than you. Some people probably get lucky and no one else is on to bid (if it's an auction) and some people don't get lucky and the price just goes up and up. It all depends. She's quite popular.
I wonder if Patricia was ever as popular as Merengue.