I work with parolees who often only have government-issued phones with maybe 5GB or 15GB of data per month, which generally only lasts the first couple of days of the month due to issues like that. I come across home pages regularly now that are >250MB of download :(
I'll try and find some. I remember the ones I hit were "magazine" style news sites. Without uBlock they are horrible with huge video payloads in the sidebars etc.