TroyBilt.com has the official manuals for various models of Troy-Bilt tillers, as of December 2015. The website provides the manuals for free in PDF format, but physical copies of the manuals are not for sale.
From the TroyBilt.com home page, click on Parts & Support, and then click on Download Operator's Manuals. Enter the part number, serial number or model number of your product in the appropriate text box, and then click on the Go button. If you are redirected to the product page, click on the Operator's Manuals tab, and then click on the link for the manual that you wish to view. If you are redirected to a list of manuals, choose and click on the manual that fits your needs.