What are these worth, and what can I sell them for?

Kruipen.com can help you out.  It will show what others are selling for.

$200 a pair if you are lucky. They've always had a poor reputation for SQ!

The photos you posted, and the wikipedia story you posted, are not of the same speaker. The NS10 ( M = monitor ) speaker in the adjoining photo of the wikipedia story is the monitor I am familiar with, as being the NS 10 M. In mint condition, I have seen people ask upwards of $500. a pair, although, I think they are not worth that much. The only market would be a recording studio setup, as they are near field monitors, usually placed on top of a console ( as in the wikipedia photos ). If you own the NS 10 ( the 1st set of photos ), I cannot say. Enjoy ! MrD.

Visit HiFi Shark and search on Yamaha NS-10. I see a number of active listings for these speakers but you have to visit the listing site to see actual pricing. Looks like some currency conversion will be necessary too.  If you click on the "sold/expired" tab, that does show prices.

https://www.hifishark.com/search?q=yamaha+ns-10

Not much and they are not the same as the speakers in Wikipedia, so you did not find gold at that garage sale.

Give them to a needy deaf audiophile.

Give them to Goodwill and take a $100 deduction.

@ebm pretty pretty funny. 

Ok Ok, I get it!  They are not worth very much, Bless you all! but I already new they were not worth much, just wanted to put an accurate price tag on them that made sense.  I didn't just buy them I have had them for years, and they're not going to goodwill, although a very kind thought.  So go ahead and say what you will,  I really like the retro look of these and it brings back memories of when I was a kid playing records on my old record player, Good Memories!  They are old and we have come a long way since, but don't forget what got us here.  Wikipedia is showing a picture of the later model and I do believe this was covering a range of speakers made throughout the years.  They started making these in 1978 and they changed over time.  That is what made this so confusing.  Anyway Thank You All for you input!  and now I will sell these now to a person that would love to enhance a retro room with some nice music coming through these retro speakers, that will enhance this type of interior design.  Thanks

@stereo5 - Thanks for that Kruipen link.  It is new to me a wonderful resource.

2nd bondmanp…
Thank you .

Just a heads up.  So we have a new member, and they get beat down. All he wanted to know is what they were worth. Not how they sounded. Not any snarky remarks.  Now not all the comments were that way, but let's be more welcoming. True comments about a speaker can be had with a more civil tongue. Sometimes I think we can be a little elitist.

not to be glib but...the answer is the same to both questions...What someone is willing to pay!