Unfortunately, amazon doesnt have a sync button for carts. Its pretty disappointing honestly. We tried the household thing and it was a mess. Youre better off just making a shared Wish List or using one login. I found some good tips on Smartphone Board for managing shared accounts better. Right now though, there isnt a direct way to see her cart on your app.

We actually found a great workaround using the Alexa list feature inside the main app. My wife and I are super satisfied with it since the list syncs automatically between household accounts. Honestly, the setup works well because you can just speak the items out loud. I used amazon cart share to get the syncing right. This is free and much simpler than messing with cart settings.

^ This. Also, unfortunately, the technical architecture of Amazon Household is still pretty fragmented. Even with the sharing features, the actual cart data is siloed to your specific account ID, so a sync button basically doesnt exist. Its really disappointing that they havent optimized this for families yet. Since you need something simple and free, here is the technical workaround I suggest:

• Set up a shared Idea List instead of using the cart for planning.
• Enable the Collaboration setting so you both have edit access.
• Check out this resource on how to share amazon cart for the specific permission settings you need to toggle. Honestly, the app is kinda a disaster for collaborative shopping. Your best bet is to treat the list as your master database and only move items to the cart right before you hit buy. It wont be perfect, but it prevents the double-order issue.