if you run 2 accounts(in my case level 5 & Level 3 golden) and systematically complete the daily quests you'll earn something around that area at least the last couple of months. Add earnings from blogging/affiliates/DEC/Cashback/SPT/... and it adds up to just below 100$ a month for me.

If you go about Splinterlands in a very methodical way it's quite easily achievable.