There is an issue with the entry fees with the storm deckathalon that after the daily's free 4 entries are used, it is charging 1000 gold per entry instead of the 4 additional credits it is supposed to be paying for. I can only assume that this has to do with the upcoming update that will be making a change to them since it hasn't been any problem before. (I'm not happy about upcoming changes to entries either)
The 4 free credits we receive work fine, but after that buying 4 credits gets me one run and then it says I have 0 credits and have to spend another 1000 gold.
I don't know if this was intentional or not but as I have been playing through the current storm deckathalon event, I have bought the 4 extra credits for 1000 gold multiple times and it says I have 4 credits to use again, but after one time through any of the four stages it says that I have no credits remaining and need to buy the credits again for another 1000 gold. I looked quite thoroughly and couldn't find a post that was made about this issue but I did see someone else comment about it in a twitter post.