Can't calculate that, until we know approximately how many users it would be, as that would determine the server setup we'd select.
Discussion
I have 1 project that will probably be in the 10-25gb range. Another that will probably be under 25 mb.
I may be interesed if the costs are affordable.
I think your first number is also MB, right? Alexandria is in the 4 MB range and our website is 16 MB. Njump is 33 MB.
Seems like circa 10-50 MB per repo, would be simplest to measure.