9. Calculating Net Pay and Spendable Income. In the above example, calculate your net pay and spendable income if you save $200 per pay period in a tax-sheltered annuity. Tax-sheltered method: Gross Pay TSA Net Pay Tax Spendable Income $2,750 $200 $ $ $ 9. Calculating Net Pay and Spendable Income. In the above example, calculate your net pay and spendable income if you save $200 per pay period in a tax-sheltered annuity. Tax-sheltered method: Gross Pay TSA Net Pay Tax Spendable Income $2,750 $200 $ $ $