What did a medieval household servant earn?
16 pennies a month, plus meals and a bed.
About $370 a month in today's gold.
A month of that pay weighs about as much as 3 paperclips in gold.
A year's contract, sixteen pennies a month, and no leaving before the autumn hiring day.

Where the money came from
This servant's pay comes from the accounts of the manor of Mote at Iden, in Sussex, three miles from Rye. Its papers were found at a bank in Rye in 1952. From 1458 the lords of Mote were the Scotts. Sir John Scott thrived there, building a strong tower in the late 1460s, and served as Controller of Edward IV's household. Women servants at Mote were paid on average 16 pence a month in cash. In 1474 or 1475 one of them, an old woman named Agnes atte Wode, fell ill for a month. She was lodged with another servant of the household, and the cost was written down: 2 shillings and 8 pence. Historians reckon that if 16 pence of it paid for her nursing, 16 pence was left for her food and bed, so her keep was worth about as much as her cash. Since 1349 the law had forbidden a servant to leave before the agreed term was up, on pain of prison, and service was hired by the year. Women's pay on yearly terms barely changed from 1300 to 1500, while women hired by the day earned more after the Black Death. At day rates, half a year's work was usually more than enough to match a year's pay in service, so the day worker earned the servant's year in six months.
Sources: ora.ox.ac.uk · ryenews.org.uk · en.wikipedia.org
What a household servant's pay bought in 1350
a gallon of ale: less than a day's pay
a day of a master mason: 6 days' pay
a pig: 4 weeks' pay
a year's food for one adult: 16 months' pay, more than a whole year of it
a one-bay cottage: 16 months' pay, more than a whole year of it
Every price of 1350, with its source, is on the prices page.