middleseat, I believe there is no charge to use your cc. The IRS is the only one I know who does that.
Iorra,
Where to Buy I Bonds
From Banks and Other Financial Institutions:
You can buy I Bonds from most banks, credit unions, or savings institutions. These
institutions accept funds and purchase orders and forward the order to a Federal Reserve Bank where the bonds are issued and mailed according to your instructions. You should receive your bonds within 15 business days and the bonds begin earning interest from the first day of the month in which you buy the bond.
Time is short to lock in this rate!