It doesn’t take much for equipment to get started. Your home computer must be able to play audio files and most companies use transcription software that is available for free. Having a good set of computer headphones will help you better hear your audio files. Some positions additionally recommend a foot pedal which can help increase your production, but this can usually come later.
These little jobs are done by people who log on to a company’s site and choose tasks, which could be as simple as clicking a link. Amazon's Mechanical Turk is one of the most well-known sites of this type. Also, there are crowdsourcing projects, which are similar to data entry, where companies engage an army of virtual workers to each do one small part of a larger project.