Newspaper advertisements can be vry helpful t reenactors looking for information about fabrics and clothing, especially for the lower sort. There are other sources that provide particular bits of information that can help us.
It is pssible to find records of clothing made for a person in account books. Here is a 1767 example from a John Carpenter's account book. He lived in Chester County, Pennsylvania.
for a cap
a tow apron
shifts made up
making a short gown
making a gown
7/- and 10/-
We don't know: how much fabric was used for these things; how many caps, how big were made for 1s? Can we assume that a cap for 1s4d was more elaborate? It cost more to make than the short gown.
Occasionally, more precise information was recorded.
". . . 3 yds makes a pettycoat." Carl R. Woodward, Charles Read of New Jersey And His Notes on Agriculture 1715-1774, (New Brunswick, NJ: Rutgers University Press, 1941), p. 376.
30 April 1776 ". . . one yard of linnen to make her an apron. Price 2s-6d & half an ounce of thred . . . Price fourpence . . . " The Diary of Jacob Whitall, Gloucester County, New Jersey 1775-1779, transcribed by Florence DeHuff Friel. (Worcester, NJ: Gloucester County Historical Society, 1992), p. 28. Note: the shifts were ready on 1 June. (p. 32)
8 May 1776 ". . . I paid . . . 3s per hrd for 5 yrds of linnen to make Peg Seeds two shifts. She being on the town. Ibid., p. 29.
15 May 1776 ". . . I bough linen for two caps for Sal Bucket cost 2s7d. . . " Ibid., p. 30.
Note: Based on the 30 April entry, we can probably assume 1 yd of linen would be made into 2 caps. Since these shifts and caps were for women "on welfare," 2 of each would have been the minimum--possibly for 1 on and 1 in the wash.
Particularly nit-picky people should consult records that list measurements, that is widths, for even more precise amounts of cloth used.