Guidance on speaker values

Brand new one can assume a speaker is discounted over 10% in the current economy.
So say 15% off list brand new first run high demand speakers..
Used speakers it all depends on the demand, the value.
For the average speaker, 50% of list.
For a demo speaker, one positive point is the warranty USUALLY starts from the date of sale. However, some speakers warranty is from the date shipped. no matter when sold.

And for demo speakers, the value is again totally based on what they are doing in the market.

So, if the speakers you are thinking of are never for sale used, and have a great reputation, then yeah, pay more.
If they are just any old speakers, then no, they certainly will be overpriced as demo speakers. since the dealer will not want to lose money on them, and you could find some for less in the used market.

Onthe other side, Demo they are delivered, where internet they have to be shipped...

Elizabeth is right on the money! I would expect 10% off a new speaker as a courtesy discount. A demo 25%-40% off depending on age-condition and demand. With a used speaker even if it's a one owner and is less then a year old I would still expect 50% off.