Everyone wants to seed, so it's over saturated. Thus you won't be hitting the limits any time soon, and if you get close you just manage it with limits.
But to answer your question, for 25TB I've seen packages that cost 20euro, which is pretty much the same as what Netflix premium charges in the US.
I'm not gonna advertise them here. Next thing you know the wrong person takes an interest in this area of the internet and spoils it for the rest of us.
Trust me, I looked at the page of my provider just now and that's what they offer.
Some ppl on these sites seed over 500 TB