The first picture shows a fired case that was made by the Small Arms Ammunition Factory in Footscray, Victoria, Australia in 1962. It was a Mk 7 .303 British ball round.
The two in the second photo are also .303 British but could be Mk II,or VI. I would need to see the headstamp to give you a conclusive answer. The .303 British is one of the most successful military cartridges, having been introduced in the late 1800’s (1889 IIRC) and still in production for military use into the 1970’s. Commercially it is still made.
For more info visit this site:
You don’t give your location, so it is difficult to say what it common or scarce in your part of the world. Australia ceased production in 1962 and MF produced post WWII .303 is very common and very cheap here. There are some specimens that command higher prices but as always, it depends upon what someone is willing to pay. If it is a particular headstamp that is missing from a collection then that person will be willing to pay more.