Freeservers.com has a free package that comes with banners but you are pretty limited with space and file sizes.
The packages go up from there. I am paying something like $18 a month and have 500megs of server space, am allowed 10gigs or so of bandwidth per month, and file sizes up to 500megs if I recall correctly.
A whole grip of email accounts too. I have a feeling I will be moving up to the deluxe package soon.
ORIGINAL: SeacretsOceanCity
freeservers.com