Hi Glenn!
Actually, that came up my mind, too, because I probably would say that also in casual speech.
But, considering the need for clarity and what had been purchased, I decided "de" is the right choice that doesn't complicate things. To use "kara", I think you have to elaborate further *when writing* into something like:
州外
の業者から買った自転車
I'd like to hear from undrentide-san, too...