When you lend money out, do you do the loan at a 1% interest rate or 18.5%?

When you buy a 30 year government bond do you get a 1% interest rate (generally whatever the 30 year bond rate is) or 18.5% for the next 30 years? <br><br>It’s strange to hear people say the government has to pay back its debt when it never has to pay back its debt. So, the real question is what percent will they pay back?