2000 HUF is a lot, but it also depends a lot on where you are and the size of the Sekler Cake. If it is a giant sized Sekler Cake at a popular location (like a Christmas market or a Spring market), it is expensive, but not extremely expensive. If it is small in size and at a not central location, it is definitely expensive.
You will find locations selling Sekler Cakes at 600-1000 HUF, but these are often smaller in size, and they are not always prepared at the traditional way.