Answer

Historical advertisements can be found in various resources, old magazines, newspapers, etc.  A few databases available via NYU are useful places to find images of historical advertisements:

• New York Times Historical [1851-2018] 

  To find ads, choose 'advanced search' and limit 'document type' to 'display ad' (rather than the 'advertisement' option).

• Vogue Archive 

  Search every issue of American Vogue (1892-current) for ads by choosing 'advanced search' and limiting your 'document type' to 'advertisement.'

Additional resources include:

Ad Access

Emergence of Advertising in America 1850-1920 (EAA)