I am not an expert on savings bonds in Quicken, but I think the best way to handle this depends on how you will be treating the interest for tax purposes. Most people let the interest add to the value of the bond and only pay taxes on it when they sell the bond. If you have a $100 bond, you could buy 1 "share" for $50.00 and periodically change the share price to match the current value. When you sell the bond, you would record all the accumulated interest then sell the bond at $25.00.If it is a tax deferred account or you are paying taxes on the interest every year, you would record Interest Income for the interest as it accumulates and let the interest money accumulate as cash in the account.
If you have a $100 bond, you could buy 1 "share" for $50.00 and periodically change the share price to match the current value. When you sell the bond, you would record all the accumulated interest then sell the bond at $25.00.