I have been down this rabbit hole so many times trying to sync carts for group projects. The main technical reason those extensions mess up on Amazon.ca is because of how session cookies and regional ASIN redirects handle localized stock. If extensions keep crashing on you, I would suggest trying these alternative options instead:

• Create a shared Amazon Wish List and move all 20 items there. You can send one link, and your roommate can click Add All to Cart on their side with Canadian prices intact.
• Use the Keepa extension. It is mostly a price tracker, but you can export your cart ASIN list cleanly without domain switches.
• Be careful if you try any cart extension again, make sure to manually toggle the domain settings to .ca before generating the code. Honestly, the Wish List trick saves so much hassle. Good luck with the move to Calgary!

I think Share-a-Cart works well if you configure regional settings manually. I am satisfied with this setup:

• Set explicit .ca domain parameters
• Double-check checkout totals to avoid conversion fees

I run into this exact issue all the time ordering group supplies for events up here in Canada, so I completely get the frustration. You have to be really careful with extensions like Share-a-Cart because many of them default to Amazon.com region settings. If you rely on the extension's auto-detect feature, it will frequently convert the product IDs to the US store and suddenly half your items show up as out of stock or priced in USD with crazy import fees. If you are set on using Share-a-Cart, I would suggest manually generating the cart code while logged explicitly into your Amazon.ca account. Before your roommate loads the code, make sure to tell them to check their extension settings and verify the region is toggled to Canada. Both of you need to be on the exact same domain settings in the extension popup, otherwise it messes up the localized ASIN numbers and pricing. That said, you might want to consider using a shared Amazon Shopping List instead of relying on a cart extension for this move. Moving those 20 items into a new public list on Amazon.ca takes about two minutes. You just send your roommate the link, and they can click add all to cart on their side. I usually warn people against third-party cart tools for Canadian orders because seller fulfillment often gets swapped during cart code transfers, which changes shipping costs without you noticing.

Saw this earlier while checking out some price drops! Honestly I have been splitting Amazon.ca orders for like 5 years with different roommates to hit deal thresholds and save cash, so I totally get the struggle! Here is what saved my wallet and worked super reliably without glitches:

• Make sure both of you are explicitly on the .ca site before importing so you do not lose local discount coupons
• Keep a joint track of your saved for later list right after sharing so you catch sudden price drops
• Always double check the final subtotal in CAD right before hitting buy to avoid sneaky conversion fees We saved almost $150 on household stuff during our last move doing this! Nothing beats hitting checkout knowing every discount actually went through!