There is definitely three inscriptions you can see a date, writing that says “for the big ‘Man’”, size of the stone 340 KTS and then some symbols that might be the artist.
The bracelet is so shiny that you first think it is new. Usually when a piece has been put into storage it will build up a tarnish, was this piece polished recently? “For the big man” definitely makes you assume that whoever made this cuff was making it for a friend. Could not find anything on the symbol. If that is the carat weight of the stone it is huge, it looks like stabilized kingman and just by itself with be worth $100.
You never know what will happen on ebay. If you can get an artist name and it is Native American handmade you will definitely help your chances. The stone is huge and some people are really going to be into that. The best thing is have an amount that you would accept for it and try it on ebay.