T-Mobile used to offer 2G internet speeds internationally in 100+ countries included in Simple Choice subscriptions. 2G is limited to 50 kbit/s, that's slower than a 56K modem.
While this absolutely fine for background processes (e.g. notifications) and even checking your email, most websites never loaded at these speeds. Resources would time out, and the adverts alone could easily exceed a few megabytes. I even had a few website block me because of my "ad blocker" because the adverts didn't load timely enough.
Makes me feel for people in like rural India or other places still only at 2G or similar speeds. It is great for some things, not really useable for general purpose web browsing any longer.
PS - T-Mobile now offers 3G speeds internationally; this was just the freebie at the time.