prisma sandal
I read numbers from between 4 to 7 gb or something, but yes they don't seem to have that clearly written anymore. and that is information from a few years back, so maybe it has changed.
Gitlab seems more transparent with providing 10gb space per free repository
If you choose to use git over plastic scm (maybe possible with plastic too but not sure) and you need more space, you can consider splitting the project up into multiple repositories. I use a git submodule, so i have a git project inside the main project git repository
or you keep the big assets somewhere else like on google drive and only store the meta files in your unity git repository. but I'm not a fan of that
also, always make sure that assets that dont need to be synced are excluded from git (with the right .gitignore)