Unlimited FTP accounts
Pay for 12 months up front and it's $4 a month.
The Outhouse was hosted at Siteground for a while. We had to move because we were a database intensive site (the whole forum and front page run on a database) that had 100 people actively posting on the forum and however many guests.
For that type of site, those unlimited plans are bullshit - they have hidden provisions about using too much processing, so there's no way you could ever get close to using the "unlimited" bandwidth or space.
What they actually hope is to sell these plans to people who want to use it for stuff like you're doing, low intensity, where you really only need, say 10GB of space and 10GB of bandwidth maybe, but they say UNLIMITEDD ZOMG ONLY $4 and it sounds great.
I sound like I'm bashing it, which I am for their business practices (which all of the big name hosts do), but for what you're doing, it's what I'd recommend.
You can find similar packages at other places like Hostgator, Justhost, etc.