You can see each level of your $5 as it grows 5% one step at a time. Think about what it would take to get the money to complete each level.
You can put your own pocket change in at first but that defeats the purpose. Think about how your $5 can earn a quarter and follow that thought process down each line of the spreadsheet.
Putting in your own money is fine at first but it isn’t sustainable. That’s why it’s better to challenge yourself to make the money bring you more. The earlier in the game that you can do this, the faster you’ll make it through 250 levels.