It's an opinion that your harmonica is worth more as a collectible than as a working harmonica.
If you wish to sell it, the $ value will be whatever you and the buyer agree is fair.
A reasonable price would be estimated at $10 - $20 USA dollars.
The physical condition of the harmonica, it's playability (for players, not collectors), and it's relative scarcity (for collectors, not players)
will determine it's value to a seller and a buyer.
The physical condition of your Educator I would be estimated at fair (salvageable with repair & maintenance), despite it's very used condition.
It may not be playable in it's present condition.
It is relatively scarce (not rare), but many are in circulation with collectors.
For more precise information, contact Harley Crain, president of Harmonica Collectors International:email@example.com