Ask HN: Provider for Secondary Phone?

It’s more and more critical to have access to the smartphone, especially when traveling. So much so that I often carry secondary phone on my trips (and was saved by it when my primary phone was damaged).

Also it makes sense to use other provider for the secondary phone (my primary provider is T-Mobile).

What (virtual) provider do you use for your secondary SIM?

Requirements:

* low ongoing costs

* reasonable data speeds

* no sudden cancelations if not used for awhile

* reasonable international roaming