Just looking at the external condition, it looks really rough. The bellows have been patched up at least 2 times and the edges of the woodwork look cracked. Basically, the cost to bring it back to workable condition is likely 2-10 times more than the unit is worth, realistically speaking.
If you got $50 for it, it would be from someone else that is not very knowledgeable. As a mantle decoration or conversation piece, as is, may be around $20-$25. I say that because my uncle just picked up two very similar ones for $40 from a garage sale locally which came with a very cool story... both were identical units from twin brothers who used to play them decades ago, and both brothers had passed away within days of each other at the age of 94.