You can buy the needles on Amazon, I'd avoid the cheapest ones, IME they're usually pretty dull.

These look pretty cool, not having to deal with a separate sharps container, and they have a prepaid mail-back disposal option apparently too. https://www.amazon.com/UltiGuard-Needles-Sharps-Container-Micro/dp/B085PY122T

I just switched to .25 2xweek and needed more needles than came in the package. I got these from Amazon and used one today with my Ozempic pen. https://www.amazon.com/dp/B085PY122T?ref=ppx\_yo2ov\_dt\_b\_product\_details&th=1