Medieval money is sometimes a mystery. The UK went decimal in the early seventies, but before that the system was based on the pound sterling, or the pound in weight of silver. The most common coin was the silver penny (1d). Twelve pennies made a shilling (1s) and twenty shillings made one pound (£1)
Until 1344 only silver was considered money. There was a big silver groat worth 4d, and pennies, half-pennies and farthings (1/4d or one quarter of a penny.) In 1344, new coins arrived - a florin or double leopard worth 6s, along with a half-florin or leopard (3s) and a quarter-florin or helm (1s 6d).
In 1351 came the noble (6s 8d). Nobles, half-nobles and quarter-nobles were minted in gold. The earlier coins were minted in silver.
Just to confuse everything, there was also the mark, worth 13s 4d. Those of you who are good with numbers (which I am not!) will realise that the noble (6s 8d) is exactly a third of £1 and half of a mark. This made counting money much easier.
Between 1279 and 1399 there were perhaps 160 different sorts of penny struck, and this was because there were several mints operating at once. Three royal mints operated from Berwick, Canterbury and the Tower of London. The abbot of Bury St Edmunds, the bishop of Durham and the archbishop of York operated private mints and the marks changed when a new man was elected to the top post.
Scotland, needless to say, had its own mints and its own coinage.