Cheapest plan here in Romania is 75 GB for 2 euro/month, then the speed is limited to 1 Mbps.

More datapoints in USD (Chile) from checking various companies:

150GB-200GB ~15 USD

400GB-450GB ~19-20 USD

Unlimited (without throttling) ~21-27 USD

This is the price after the new client ~20% discount expires (generally 6 months). The unlimited and higher tier usually include stuff like Amazon Prime Videos subscriptions, local IPTV or roaming gigs. All plans obviously include calls and texting.

Data point: I'm in the US on an old pre-paid plan that gets me 5GB per month at fast speed, dropping down to unlimited "2G" speed after that cap is hit, which I've done only twice in the past 12 years. $30 per month, and I always "bring my own device" (ie, I only buy unlocked phones, not through the carrier). I haven't shopped around for a while.

USA, paying $15/month for the cheapest T-Mobile plan. I only use a few hundred MB per month typically.

I'm in WA - I pay $20/mo for 15GB on Mint Mobile. I used to do $15/mo for 5GB but kept sometimes bumping into it (tethering and stuff) so I just bit the bullet and upgraded.