Copper is a very good conductor but is very soft to be used for many applications. Brass, an alloy of copper and zinc, is harder than copper, and is used to make locks, ammunition, musical instruments, etc.
Bronze is the alloy of copper and tin. It has improved corrosion resistance and is thus used in sculptures.
Solder is an alloy of tin and lead. It has a low melting point which is why it is used for soldering (connecting parts of two different metals).