Welcome to the Harmonica Club.
We need more information about your Hohner Echo Bell harmonica, to make an accurate appraisal. If you post a picture or pictures, we will be able to give more information.
Go to this e-mail for more information:firstname.lastname@example.org
The monetary value of your harmonica depends on it's condition, relative scarcity, and size.
Generally, the more reeds a harmonica has, the more valuable it is for performers. The more scarce it is, the more valuable it is for collectors.
The monetary value is whatever the seller and buyer agree is a reasonable price.
You will never make a fortune selling used harmonicas.
On your Echo Bell tremolo harmonica:
How many pairs of double vertical holes does it have on the mouthpiece?
How many bells are attached to the top cover?
Is it a re-issue, or an original tremolo with bells?
Does it have a mouthpiece on only one side, or on 2 sides?
What printing is written on the covers?