In most Western European languages, the construction uses "change" rather than "buy" or "get a new." (Readers who are familiar with other languages than I am, please comment!) Speakers of these languages will then use the same construction when speaking in English, e.g, "my computer keeps crashing so I need to change it" or, "oh, you changed your car." I've also heard this construction in English from speakers from Africa and Asia, but I don't know if this is influenced by their native languages or by Western European English.
It's kind of interesting that the American construction of "get/buy a new one" seems to be an anomaly. Again, I'm working with a limited sample size here, and would love to hear from people who know other languages than I do. But it seems like the American construction focuses on purchasing something and tends to lead toward a discussion of how and why the person came to have a different item, while the constructions in other countries seem more neutral and less oriented toward consumerism and status. I'd love to know if there are even different constructions in other places (particularly places where making a living and having belongings is difficult) and/or if there are places where it's not polite to even bring it up.