How To Obtain A Reducing Sugar At Home?
As permeakra mentions, glucose can be purchased pretty easily. It might be labeled as "dextrose". 

Another commonly available is maltose (or malt sugar). 

Sucrose (or table sugar) is not a reducing sugar, but one of its constituents (glucose) is. Glucose can be made from sucrose by heating with a little bit of acid to make invert sugar syrup. Invert sugar is approximately a 1:1 ratio of glucose to fructose, and only the glucose in this mixture is reducing. An example procedure can be found here:How does adding lemon juice to sugar make better caramel?. Honey is a naturally occurring invert sugar.