Can't find the price tag to turn Review Checker on

Tried Review Checker when it first came out. Liked it a lot. With the most recent Firefox update, I seem to have lost it. It doesn't come up automatically in Amazon, an… (tuilleadh eolais)

Tried Review Checker when it first came out. Liked it a lot. With the most recent Firefox update, I seem to have lost it. It doesn't come up automatically in Amazon, and I don't see a price tag on an item description page to turn it on. The Firefox Settings describes Review Checker, but I don't see a way to turn it on there, either.

Asked by John C 4 lá ó shin