[Cthulhu_]

Amazon is the American version of Temu, Aliexpress, etc nowadays; I wouldn't use it for anything but their own products (Kindle). For specialist items like the cello strings you mentioned, music shops are thankfully still a thing, both online/webshops as irl ones. I'd go there instead. Same with books.

[okasaki]

It's much worse than aliexpress. Ali won't send you used items or returned bricks.

[razakel]

It's borderline impossible for the high street to compete on fungible goods like art supplies and books. The only real value in those shops is knowledgeable and passionate staff who share your interests.

[nosioptar]

Agreed, I normally wouldn't buy strings from anyone but a reputable violin shop. The strings I wanted were new and none of the small shops could get them at the time.