Where you live will make a difference to the price.
I have never bought an NMax but I have bought a few of the smaller PCX's.
An 8 - 10 year old one goes for about 50,000 baht.
Then again, cars and bikes on the island are more expensive than on the mainland.
I have also bought a few, old Honda clicks etc. 12,500 with no book!
God knows how old they are but they are still running.
If it looks great and runs lovely, why sell? Yes - a few quirks but.......