After having slept for a few days with lots of painkillers (to deal with the shin splints!) and other things - I remember a few other tips.

Usually when selling (although the photo there is clear enough to see these and you have covered the rest) it is best to state

1) number of keys on the keyboard eg 41 keys (didn't count yours!)

2) number of bass buttons eg 12

3) number of treble and bass registers - in your case - nil of each

This makes it look like what you are talking about.... :-)

4) any 'special things' about the instrument - this can be many things, but sometimes it can include special register arrangements - not all boxes are 'standard' - in this case, there doesn't look like anything, such as 'chin masters', 'wrist masters', etc. If there are a lot of 'register switches', especially if the bass has more than 2 - it can be helpful to give a closeup photos of such things, or else you'll just be asked for more info by those who know what they are looking for.

If you state all this up front, people don't need to ask questions.

I suspect a big flurry of bidding in the last few minutes, by those who are 'collectors' or those hoping to buy it cheap to resell it.

I'd say your price is about right.