Amazon often stocks and ships products from third party sellers too. Most people don't bother checking that. They just assume it's straight from Amazon themselves.
I wouldn't consider anywhere other than direct from their own websites.
Ledger have an official Amazon store in several countries which you can find from following any of the links on this page:
https://www.ledger.com/pages/retailers. Alternatively, if you are searching on Amazon, it should say the words "By Ledger" underneath the product name. If you don't follow either of these steps, you will likely end up buying from a third party seller which is inherently risky.
Having said all that, even buying from their official Amazon store still adds yet another step in to the supply chain. Although highly unlikely to cause any issues, it is riskier to buy from Amazon rather than direct from Ledger themselves.