We have been buying extra strong PG Tips British tea from Amazon because we think American tea is way too weak. 3 boxes of 80 were about $40 last time I bought them a few months ago. They’re now $80. Thankfully we discovered we can get an order of 6 for $60, but we have to wait until mid-February for the to arrive. Meanwhile, a single box of the same tea, which we'll have to get in the mean time, is $20. Yes, a single box is less per box than a 3-count box order, but you still save if you buy 6 boxes. How does any of that make sense?
Although they're available you don't need an extension or app. They have a website where you can view price history and set email alerts. It works great, I'm still getting price alerts I set up years ago.
Not sure about camelcamel, but I use Keeps and it has a price history chart so you can see the fluctuations of every product. They do go up and down like the stock market!
But more importantly, I set price alerts (same as camelcamel) and that really does make a massive difference. I've been doing it with grocery items lately, but even on high-value stuff that I'm willing to wait on can bring substantial savings.