The picture shows a selection of Binding Posts. There are variations of these which may also be used for binding albums, although not recommended for a "proper job". If you are looking for them they might come under another name such as ~ Chicago Posts ~ Chicago Buttons ~ round head stud screws ~ barrel nuts ~ screw fasteners ~ hex sockets ~ screw posts ~ binding screws ~ interscrews ~ nail-rivet ~ furniture-sleeve nuts ~ and I would be pleased to list other variants as they are brought to my attention [mail@highview.co.uk].
The prices of binding posts varies greatly, sometimes without great reason. They are unlikely to be found in high street stationers. In cities a good office-supplies store will be a good place to start looking. A telephone call before travel might save a wasted journey.
A quick browse on the web has shown single brass posts at £1 each one they come as pairs, plus carriage, from two separate suppliers, whereas the nickel plated ones can be found as variety packs of ten-each of five sizes for under £10. In general the nickel plated ones are easiest to find, and the cheapest. Brass plated is also available, moreso than genune brass.
Some suppliers might omit the word "plated" in their descriptions. Also watch for "brassed" or "brass tone". In my experience some people are keen on acid-free long-life paper, but forget that rust stains will spoil even the best paper. I have lived near the sea for fifty years, which is a severe test, but I have found a lot of "brassed" items will rust within a year or less.
Mechanically all the illustrated itmes are variants of the nut and bolt[124387].
Sample Here is the code for a link to a local USP [122932]