What is the scope of a psychology degree in the US in terms of available jobs without a master’s degree?

You can offer just a bachelor's degree and get a job such as in marketing, retail management and customer services but it's the training specific to a job that is the key rather than a master's degree. The master's gives evidence that you can study to a higher level successfully, and that you have the personal discipline to follow one line of academic enquiry and increase our body of knowledge.

However, to carry out any job there is nothing like hands-on experience. Different jobs require different kinds and extents of training. In clinical psychology you have some further years of study, albeit much practical, before you qualify. The same for forensic, industrial, educational psychology. Other fields, such as management, retail, the company may have its own in-house training. Don't ever think a bachelor's degree is enough in itself.

Available jobs in the United States for people without a master’s degree in psychology primarily include careers in clinical, counseling, or health settings such as those found in schools, private and public employment, hospitals, clinics, and correctional facilities or probation offices.

Also, because psychology graduates with a bachelor’s degree typically have good problem solving, analytical, research and writing skills they can easily find work in many other industries. The United States Bureau of Labor Statistics projects employment for psychologists is projected to grow 14% from 2016 to 2026. The average overall growth rate is 7% for all occupations so this is certainly encouraging for psychologists.