If the transcript is easily obtained, often it will be sent at no charge. Some firms charge but that is rare. If the file is older and warehoused offsite, then good luck. There are some commercial services for obtaining prior testimony. They include IDEX and Westlaw which has an agreement between the U.S. Court Reporters Association and the National Expert Transcript Service .
Users can preview abstracts of transcripts and then order the full-text document.
Conclusion Finding and investigating expert witnesses is often time consuming and expensive. If you have the proper information and budget, you should turn up some nugget that will be useful. If not, a well documented search on your part will be the evidence you need to backup your efforts. The coming digital workplace will, I suspect, allow for easier access to expert witness materials as paper storage disappears and documents stay in digital format. Until then, know that an expert search is costly both in staff time and money.