Mouthpiece - A quality french horn mouthpiece can cost $60 to several hundred dollars.Also intermediate will sometimes come with a detachable bell for easier transportation of the instrument. Some professional models will have hand lapped rotary valves/slides, and hammered/annealed bells. Double french horns will typically be a kruspe or geyer wrap. Features - Most French horns are either single F or double F/Bb.Case - Quality french horn cases can range from $100 to $300 and should be considered when looking at the whole cost of the instrument.Unfortunately, some french horn manufacturers use low quality materials, which most of the time results in an instrument that cannot be fixed. Brand/Manufacturer - Not all french horns are built the same.Condition - New or used, as well as any needed maintenance can determine the cost of a french horn.Intermediate french horns will typically incorporate more copper content in the brass (gold brass) of the bells and slides. Material - Student models will typically have durable nickel/silver inner and outer slides and yellow brass bells.There are several things that determine the overall cost of a french horn: Intermediate, or step-up french horns usually range in cost $3,500 to $4,500 and entry level pro french horns (still largely played by advanced students) around $4,500 and up. Beginner french horns usually range in cost from $1,200 to $3,500.