Complex sentence: Other coins are used as money in everyday transactions, circulating alongside banknotes: these coins usually worth less than banknotes: usually the highest value coin in circulation (i.e. excluding bullion coins) is worth less than the lowest-value note.
Split into simpler sentences: Other coins are used as money in everyday transactions, circulating alongside banknotes. Usually the highest value coin in circulation (i.e. excluding bullion coins) is worth less than the lowest-value note.