Its difficult to put an exact number on what I have earned. There's too many aspects and working parts. For example there's the SPT token earned for blogging about Splinterlands when using the SPT tag. There's the DEC token that can be earned for winning ranked battles and placing in tournaments. There's the growth of card prices. I suspect we see another wave of growth once land is implemented to the game. An example of ROI: A Plot of land in Splinterlands originally sold for $10 USD. Today some have sold for $200-$250 USD.