The term "marginal dollar" refers to an additional or incremental revenue earned from selling one more unit, attracting one extra customer, or generating an added penny in profit. Full definition
Even if you're paying a lot of taxes now, you're talking marginal dollars when you look at current contribution, and average tax rate when making withdrawals. (money.stackexchange.com)
But let's assume that you are in the top 1 % of income earners and your last marginal dollar does fall into the highest of tax brackets. (thecollegeinvestor.com)
Based on the demographics of an economy, if marginal dollars tend to be saved versus spent, stimulus would affect the economy differently: (alephblog.com)