Apprentice Indentures-down loadable free from The National Archives site.
The register of duties paid for Apprentice Indentures between 1710-1811 can be searched on a pay per view site. The Society of Genealogists also have a database that can be searched by members or on a pay per view site.
What is not widely known is that the same records can be freely accessed at the TNA site. You can download the records at Ledger Duties Paid on Indentures
You will have to search through the records yourself, but they are free. Warning the down loadable file is a PDF about 39.9mb in size.
National Archives Podcasts.
Another invaluable and free resource available on at TNA website are podcasts. They can help you in many ways including how to research the many resources at the Archives.
They range from: English burial and cemetery records online and on film. The untold story of women in the Crimean War. The Land Tax 1692-1963. Nineteenth century soldiers: getting the most from online resources. Suing and being sued - finding people in legal disputes and many many more.
The podcasts can be found at National Archives Podcasts