How do I edit a page to enable price tracking?

[J___T]

I've noticed a number of pages that don't give the option to price-track the release. In perusing the editing choices, I haven't noticed where price tracking is turned "on" or "off."

Is the lack of trackability an oversight on the part of the people who created those items' pages, or a conscious choice to prevent tracking of certain releases (and if so why)?

How do I edit the page to enable price-tracking of these items?

Thanks!