Chapter Griffen Horse to Groat of G by Brewer's Phrase & Fable

respecting precedency. (See John O' Groat.)
   Blood without groats is nothing (north of England), meaning "family without fortune is worthless." The allusion is to black-pudding, which consists chiefly of blood and groats formed into a sausage.
   Not worth a groat. Of no value. A groat is a silver fourpence. The Dutch had a coin called a grote, a contraction of grote-schware (great schware), so called because it was equal in value to five little schware. So the coin of Edward III. was the groat or great silver penny, equal to four penny pieces. The modern groat was first issued in 1835, and were withdrawn from circulation in 1887. (French, gros, great.) Groats are no longer in circulation.

"He that spends a groat a day idly, spends idly above six pounds a year." - Franklin: Necessary Hints, p. 131.