I don't know what the costs involved are, but Cox has business internet, which if it is similar to Comcast business is cap free. I've had business for close to a decade now because of that reason alone. Generally you pay a bit more for a bit less speed, but if your only other options are shitty dsl, overage fees, or a second line...it might be worth it to look into it. The ONE time someone asked me what my business was, I just told them I do consulting and freelance graphic design work which requires sending huge files back and forth repeatedly for the smallest changes. They really don't give a shit, there is no real requirement that I'm aware of for you to have an actual business, but no reason to flaunt that in their faces either if they ask.
Oh, and when I say a bit more cost, of course I mean a bit more than the normal residential price, not any "first two year" deals or whatever. So if you're currently doing that game, yeah you're gonna notice a decent price hike.
Anyway, still might be worth checking out if you really have no other options.