I've forgotten much of what I know about it but it is very common, even exceedingly common compared to the number of telephone token collectors. We're probably talking at least a couple hundred thousand.
I don't know. First you'd have to find a public pay phone. I don't know about France but that is getting difficult to do here in the US. (Although in our town here we still have an actual phone booth!) Something else from the past that's long gone. Pay toilets. I don't think I have seen one of those since the 1960's. (It's possible to collect pay toilet tokens too!) Hmm no tokens on ebay, but I did find a stock certificate for the company that made the pay toilet locks.
I'm extremely lucky in this regard. Most US telephone tokens are Illinois and a disproportionate number of these are Chicago. Being near Chicago I'd see these all the time and pick them up for nothing. I had nearly 50 in my collection before I learned what they even were! My collection now is very extensive and I have more than are listed by Targonsky in the catalog though I do collect varieties as well and don't have them all yet. These are a lot of fun to collect and trade but there are very few collectors. Many of these tokens were turned in for the scrap drives in WW II and they mostly had mintages of only 1000 so some are quite rare. The most desirable in my opinion is one made for the 1933 worlds fair. It's not especially rare but the demand for it is very high. Most TT have light wear with a few that have heavier wear. They tended to be used almost immediately in hotel telephones which had special slots that would only take the issuers token. This was to gaurd against "plug nickels" which were amusement tokens with a bit of lead hammered into the center hole. These would sound just like nickels when they struck the bell in the telephone. The operator would connect the call and the hotel would be out a nickel. This might have been an especial problem in Illinois because the Keane Gaming Company et al made numerous holed tokens which were used in nickolodeons as well as gum and candy machines extensively. This is not especially clear as is the reason that so many amusement tokens are from Minnesota. In many cases it just might be that a salesman was especially effective in these areas. There are also a large number of encased pennies from northern Indiana though this one is more obvious. I think the day of telephone tokens will come since they are so interesting and historic. There are examples from other states as well, especially California. Brazil and Italy have issued large numbers of these as well.
there are a few different ptt telephone tokens i have this one and one other in my collection of telephone tokens as well as some from italy, israel and argentina
I have a bunch of US ones made of copper or brass. They look much like the coins the mint destroys. They have a wavy look.