This depends on whether you get accessories like a case or choose a marching or convertible model. Most of the time, you can expect to pay a few thousand dollars. Anything around $2,000 or higher is more of a professional-grade instrument and will be suitable for college students and above. If you have a child interested in joining their high school marching band, schools usually have a budget to help purchase instruments, or they have nearby music stores where you can do rentals.