Help with Spark Plug Choice

[Already Gone]

I am going to change the plugs in my bone stock all original 72 c10 with a 350 4bbl. and 87,000 miles. If I keep the truck 10 more years I may, at the most, put 10/15,000 miles on it over that time. Other than installing the Pertronix Distributor, ignition wires and one of their 40,00 volt coils I have waiting to be installed and maybe putting a dual snorkel air cleaner on the truck in the future the engine shall remain stock. My research has told me there are 4 different types of plugs, copper, platinum, double platinum and iridium. The prices vary from 1.89 for copper plug to 8.25 for the iridium. Can you guys/gals give me some real world info on what you are using for plugs. If my old memory is functioning correctly I believe that unlike todays vehicles the plugs in these engines form the 70's needed plug changes every 10,000 miles