Microsoft Personal Shopping Assistant was originally released last year as a Chrome extension, and has slowly expanded to more web browsers since then. It has gained a somewhat unpopular reputation, due to Microsoft recently displaying ads for it in Windows 10. Still, if you happen to use it, you'll be happy to know that an Android version is in development.
Shopping Assistant detects when you are shopping online, and adds items you look at to a 'Browsed' list. You'll get alerts when products go on sale, and you can move them to a 'Saved' list for easy access. All of this data is synced across any devices with Shopping Assistant. Sharing a link to Shopping Assistant from any Android app will also add items to the Saved list.
At least, that's what the app is supposed to do in theory. Right now it is rather buggy, with items never being automatically added to the 'Browsed' list, and Saved items never showing any product details. But it's still in beta, so this kind of bugs is to be expected. You can grab it from the Play Store below.