Exactly what I was looking for
I had never heard of Born Primitive before a google search for bra inserts led me to the site. (I wasn't sure if one could even purchase the inserts separately, it was a complete shot in the dark.) These were very reasonably priced, so I grabbed a few and hoped for the best, and I'm glad I did. They fit my bras well and wash easily. I haven't had them long enough to attest to longevity, but they seem to be of high quality.
I have been making an effort to support small businesses, and this was another positive experience. You may pay a little more up-front, but it's more than worth it.