I buy crowns like they're going out of style, and most times I buy them on sale. They're almost always on sale in some form... 50% extra crowns, 25% off... it's pretty frequent...
There's a 25% off sale on everything until the end of tomorrow (Monday). That would make 60,000 crowns $60, the same price as they are when they're on sale by themselves.
Otherwise, when I was here regularly, they seemed to cycle crowns, a year's membership, and a combination of the two about every two months.