New Member To Coin Forum

Hello folks, my name is Jonny. I recently acquired a bunch of coins. I have been "saving" (not an avid collector lol) coins throughout my whole here and there. I have always been fascinated by coins, honestly I think the childhood feeling of !pirates treasure! when I see or find a great one has somehow followed me through life and still present lol. I have a question about one of my coins if that's okay? I have been trying to learn about the more overwhelming side of coin collecting, and apply it to/gather info about my coins. One of them I have is a 1957 50 PTAS coin with a "58" inside of the star, it also says "Una Grande Libre" along the outer edge of the coin. My question is, many of the websites I have seen say this coin is worth (depends on its condition, which I have learned is everything) an average of a few hundred dollars, in F or VF quality. On ebay there are a whole lot of them that are the same as mine according to the sellers description, but listed AND selling at $10 give or take... so I guess I am confused lol. Many of the ebay coins look like they are in great condition, had this coin lost value? I'm sure this is totally a noob question too haha, but I just don't understand is all. Anyhow, thanks for having me on y'all's site and I hope everyone is well! Thanks!