Amethyst uses about a gig a day for me. I'm abroad, so that's a few dollars a day via silent link. And I'm not on it for more than 30 minutes a day right now, and all the media downloads are off. It's all from events. @Vitor Pamplona

Yep. That's about right. Events +translation models (50mb each). You can generally see the amount of MB used for each relay in the relay list screen.

This tool might help

Plebs vs. Zombies

Plebs vs. Zombies | Nostr Follow Manager

Clean up your Nostr follow list by identifying and removing dormant zombie accounts. Hunt zombies, manage follows, and keep your network alive!

until you posted a screenshot, I did not know mine is the same. But I do not check my following un amethyst. I checked mine in yakihonne or primal. My notifications in pokey. 😬

Thats another thing I've noticed recently - the relays often show no data, but further down the list, the other relays where I'm picking up other people's events, are really busy. Is 50mb really right? That's a lot of data per event. Most of the time it doesn't matter as I'm on WiFi, but this month in particularbI'm noticing all these odd behaviours and the data usage on mobile has been way beyond the normal range - to the extent I've actually nearly run our this month.