United States savings bonds are debt securities issued by the United States Department of the Treasury to help pay for the U.S. government's borrowing needs. U.S. savings bonds are considered one of the safest investments because they are backed by the full faith and credit of the United States government.
The reason that their value is zero at initiation is that they are formed in a way that is neither beneficial for the short of the long party therefore they have a value of 0.
The entry to record the purchase of supplies will include a Debit to Asset Account - Supplies and a Credit to Liability Account - Accounts Payable at value of $460.