Right now I have 50 or 60 items in the Saved Items part of my Amazon shopping cart. I go to Amazon a couple times a day and check the price changes in the cart.
This morning:
Important messages about items in your Cart:
23 items in your Saved Items have changed price.
There's one item that typically goes from around $6.50 up to $11.99 and back again every two to three days. Sometimes in chunks, sometimes all at once.
Another item, one penny. Daily. Back and forth.
Occasionally, I'll catch an attractive price drop and jump on it.
Since Amazon began adding sales tax for my state (which, BTW, never seems to be calculated correctly) and changed the free shipping threshold, my purchases there have dropped a lot.