your scouts have upkeep cost
this is the cost of having ships in your fleet when you spend turns
to get rid of this cost, you need to get rid of the ships
go to "disband fleet"
and type in the number of ships you want to get rid of
but if you are in debt, then that will add another cost of debt interest, and if you click "income" in the top left corner of the command screen, it will show you what is costing you so much, and you can act accordingly (if your debt interest is much greater than your income, then you have to restart becuase you are too far in debt to get out)