I'm not an expert, but usually bonds are bought at a discount. The city would sell 1.5 million worth of bonds for 1.3 million, for example. The effective interest rate comes from that discount.

That said, they don't seem to provide a lot of details and I've seen some wildly misleading numbers from Strongtowns. They're not to be trusted to provide objective numbers.

We can expect 3-4% inflation for the next 5 years as a result of the Fed's stimulus programs.