Wage-and-salary medical transcriptionists in the United States had median hourly earnings of $14.40 in May 2006. The middle 50 percent earned between $12.17 and $17.06. The lowest 10 percent earned less than $10.22, and the highest 10 percent earned more than $20.15. Median hourly earnings in the industries employing the largest numbers of medical transcriptionists were:

Compensation methods for medical transcriptionists vary. Some are paid based on the number of hours they work or on the number of lines they transcribe. Others receive a base pay per hour with incentives for extra production. Employees of transcription services and independent contractors almost always receive production-based pay. Independent contractors earn more than do transcriptionists who work for others, but independent contractors have higher expenses than their corporate counterparts, receive no benefits, and may face higher risk of termination than do wage-and-salary transcriptionists.

Source: http://www.bls.gov/oco/ocos271.htm