Find samples of business testimonial letters on the website, SampleTemplates.com. Templates on the site are free and downloadable. Testimonial letters are also referred to as recommendation letters.
Sample Templates recommends that testimonial letters be gathered only from customers whose experiences with the company are extensive enough that they can make a valid judgment about the company's services or products.
SampleLettersWorld.com includes dozens of templates for letters of recommendation, including recommendations for products and services. The site also includes examples of weak letters of recommendation.
The website Scribd.com includes a template for a letter to be used in soliciting testimonies from previous clients or customers.