Commercial tests are usually available for purchase by contacting the test publisher. Publishers usually have different pricing structures for private vs. organizational use. Additionally, individuals may have to fill out questionnaires designed to assess their ability to successfully administer the test.
Many psychological tests and measures can be obtained freely or at a low cost through published research. Here are a few tips for finding and obtaining these unpublished psychological measures.
1. ETS Tests - This is one of the largest collections of tests and measures. You'll find commercial and non-commercial tests, but the interface allows you to find tests available for free downloads or purchase through the ETS website.
2. Search PsycINFO - Many tests have been indexed and are possibly available in full-text from PsycINFO. Combine your search terms with the words "scale", "instrument", "evaluation", "survey", or "assessment".
Also try including the word "appended" as a Test & Measures search, by selecting Test & Measures from the search drop-down box. This will retrieve articles with the tests appended to the article. Limit to full-text for the PDF or request a copy via ILL.
3. Search the internet - It is possible to find some unpublished, freely available tests via Google.
4. Ask the author - Many tests and measures may be unobtainable by any other means. Asking the author directly is a common approach for obtaining copies of an unpublished psychological instrument.