Altec lansing Melodist model, i think...
OK, we are going back to the mono era here. So I suspect you have only one speaker unless matched in the stereo era.
Prior to 1950 the bass driver was the 700 B. In this case there will be a knob on the back marked HF. If there are just terminals then the driver is the 755A or 801A. If you open the cabinet the back if the magnet will be unmarked plain brown if the 755A. I think this was made until 1954.
If it has the the Altec 401 A it will be marked on the magnet.
These speakers were designed so they could be put on an LP record shelf.
Now the 755A version is the most valuable as the 755A was the driver in the AR 1 speakers. Restorers are always on the lookout for those drivers to restore AR 1s and will pay $300 to $600 for a good working driver.
The complete speaker is only of use to a museum What it will fetch will depend on who is in eBay after it at the time.
If it does not have the 755A driver it probably will not fetch much, say around $100, but you might be lucky and have more than one collector after it to start a bidding war.
Having said that it is an interesting curio from the past.
Before listing you will need to test it and confirm it is a working speaker
