A spending Bill has to show how it effects the budget. Contrived example.

Say it spends a billion dollars. But it needs to be balanced. So they tax pork rinds at 99% to balance it.

Now the paper result is the bill is balanced. Ignoring the real world result that pork rind sales plummet.

So on paper everything is fine. In reality an industry is destroyed.

This happens constantly. They just try and keep it from being to absurd.