Pewter is an alloy of tin and a variety of other metals. Pewter tankards are quite common. Pilgrim's badges were often made of cast pewter. Period pewter often contained lead, a toxic metal. Modern pewter is an alloy of tin, copper and antimony and is more properly called Britannia Metal.
Since pewter has a low melting point, it is relatively easy to work. Moulds can be made in soap stone or cuttlebone.
Pewter was easily available in the high middle ages it was much less common in the early medieval period. However, it was still expensive and the ownership of pewter in the 16th century was not something that would be achievable by an average person. It was eventually replaced by porcelain tableware during the 18th century