[scarecrow]

Hi James, welcome to Toyark!

Someone will inevitably explain this better, but I can give a quick explanation for the three types of figures you listed above.

First, the only difference as I know it between variants and chase variants is just that chase variants are more difficult to attain, and "chase" figures are usually confirmed by manufacturers of the toys. Regular variants are just redeco's or slight re-toolings of existing figures, but you probably already knew that.

Running changes on the other hand is when a certain aspect of a figure is changed after the first production of the figure and/or tooling of a figure, and the change ends up being a permanent replacement to the original.

For instance, when they did the Doc mail-away for the 25th Anniversary GI Joe line, there was a "slit-wrist" version of Doc initially given away, and then was fixed to be more aesthetically pleasing, and remained until the end of the figure's production.

Variants generally are more difficult to find that regular versions of figures, but it seems like of late the variants are as simple to get as the originals. It's good to do a little research because sometimes dealers see variant and hear "jack up the prices on this". It seems that with novices the general consensus is that variant = more valuable, which isn't always the case.

I hope this helps you get started a little, I'll let someone else answer your other questions. Have a happy 4th!