of collecting includes a representative sample of each major design and change, but excludes lesser variations (e.g., signature combinations, Treasury seal, overprints, etc.). Collectors build variations of the ultimate set. For example, many do not include gold due to the prohibitive cost; other now omit designs before the year 1800. These are the most expensive due to several factors: Poor quality of material, primitive machinery and working conditions, minuscule production numbers and general wear and loss after 200 years. Most designs cover decades but some were minted for only one or two years making these the rarest of the entire set. It is not a coincidence that many of these were also struck prior to 1800 when the Mint altered designs in response to unfavorable public opinion. The most famous of these short-lived designs are the half cent (1793), quarter (1796), Draped Bust, Small Eagle half dollar (1796–1797) and the three large cent designs minted in 1793 - Wreath cent, Chain cent and Liberty Cap Cent. The Haig Koshkarian Type Set , one of the finest ever assembled, was auctioned in 2004. Examples - copper, nickel, silver, gold Complete Type Sets - Silver / Copper / Bronze / Steel / Clad coins Complete Type Sets - Gold coins Footnotes Numismatics