Qualified Friends and Family

All of us know people who may be qualified to participate in a study. This is especially true of products that are used by the population at large and for whom the characteristic audience is very broad-based. You might have friends or family who share all the characteristics of your internal end users with the exception that they do not work for your company, which is a real advantage.
If you do end up using friends and family in your study, make sure that your relationship does not affect your professionalism. When testing, do everything exactly as you normally would, including reading the orientation script, being sure not to talk about the study until after it is completed, and not being overly chummy during the test.