I would say no. Crowns randomly go on sale maybe 3 times a year. Xmas / new year is a common time. I think they were on sale recently as well. They do not go on sale when you really want them . Not that you could buy the expansion with crowns anyway.
PC EU (EP): Magicka NB (main), Stamina NB, Stamina DK, Stamina Sorcerer, Magicka Warden, Magicka Templar, Stamina Templar
PC NA (EP): Magicka NB