Upgrade prices for United trips to Europe seem to be fluctuating like crazy right now. On the UA Reddit group people are reporting things like $300 premium plus upgrades, and I just checked one of my own upcoming flights to Europe and the price for both PP and Polaris just dropped by like $1000 since this morning. Still not low enough for me, but if either drops by a little bit more I might jump on it.

Is there any kind of app or alert or service to subscribe to (totally happy to pay) that monitors this? Or is this just a matter of logging into the app and checking price offered manually on like an hourly basis?