Oh I’d say its more than 100Mbyte/month and less than 1PByte/month
Really there will be many factors affect the quota of data needed. If you say run a 10GB vault then that will be much smaller than a 2TB vault, then the number of nodes compared to number of people accessing SAFE will also be a factor. We need testing to get some realistic figures and that won’t be till at least beta testing, the alpha vaults might give an indication but not reliable figures.
I’d say if you want to earn a good amount of SAFEcoin then you’d need say between 300GB to 1TB per month quota, then tailor you vault/node to be in that range. This is working back from the bandwidth quota to vault size rather than picking a vault size and working out the quota needed.
This is the crux of the matter. Since SAFE is targeted at the home user using spare resources (disk, cpu, elect, quota, etc then you will have a hard time.