Using the FinAid Student-Loan-Prepayment Calculator, I found the following analysis using 50% of my net pay as the monthly payment.
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Loan Balance: $100,000.00
Loan Interest Rate: 6.80%
Loan Term: 10 years
Regular Monthly Loan Payment: $1,150.80
Extra Payment: $751.00
Extra Payment Frequency: Monthly
Without Extra Payments
Number of Payments: 120
Total Payments: $139,247.37
Total Interest Paid: $39,247.37
With Extra Payments
Number of Regular Payments: 63
Cumulative Regular Payments: $72,500.40
Number of Extra Payments: 63
Cumulative Extra Payments: $46,566.22
Overall Total Payments: $119,066.62
Total Interest Paid: $19,066.62
Savings
Prepayment Savings: $20,180.75
Reduction in Interest: 51.42%
Reduction in Payments: 14.49%
Reduction in Loan Term: 4.8 years ( 47.50%)
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So I can pay this loan off in 5.2 years and save $20,180.04! That's awesome!
I'm going to ride my bike and get a bike trailer for groceries and stuff too. That seems like a no-brainer. If I need a car for inter-city travel, I'll just rent one.
http://www.finaid.org/calculators/scripts/prepayment.cgi