I am happy to do the calculations for you.

If you want an income of $2,000 USD per month, that comes to about $65 per day.

At a price of $0.55, that means you will need to earn $65/0.55 = 118 CUB per day.

The daily yield on CUB Kingdom is 0.15%, so to earn 118 CUB per day, you will need 118/0.0015 = 78,666 CUB.

or roughly $43k worth of CUB.

Please remember, the price of CUB goes up and down, so you will probably make (or lose) more money through price movements.

Also note that over time, unless the CUB burns exceed the inflation the earning rate on CUB will decline. At the moment, the daily CUB burns, represent less than 1% of the new CUB inflation. this could change with growth of the kingdoms though, but could reduce as the price goes up (Like we are hoping for!)