The worth of sterling silver at any one point is relative to the silver spot price. This figure is the amount per ounce or per gram that buyers can pay for a given security - in this case, sterling silver - at a specific time and place. Spot price changes over time, meaning the worth of sterling silver in one particular month isn't usually the same as its worth just 30 days earlier. Bulk trading that takes place at a COMEX (commodities exchange) has a significant influence on the spot rates of precious and semi-precious metals, including silver.
The spot price is only a benchmark for the worth of sterling silver. Often, buyers and sellers use this number as a baseline to gauge what they're actually willing to pay for the commodity. As you'll find out soon, the sticker price is hardly ever the final sale price.