What's the easiest way to earn money?

https://preview.redd.it/ngethsaspbhe1.png?width=1591&format=png&auto=webp&s=e681425c3aa989d3d5d353cd7bb4f36e16556c1a

Here's what I have as of now. I've not unlocked any technologies yet because of financial issues. What's the easiest way I can get a huge sum of money?