Fine silver, or pure silver, is a very soft and malleable metal. It can be damaged easily so it is often combined with other metals to make it more durable. The most popular silver alloy is sterling silver which is a combination of 92.5% silver and 7.5% copper.
Copper has been deemed the best metal to combine with silver over centuries of trials. While it is possible for any metal to make up the 7.5% non-silver portion of sterling, copper improves the hardness and durability without taking away from the beautiful colour of silver.
Pricing for silver pieces is generally more reflective of the intricacy of the design and the skills of the craftsman rather than based on the metal itself.