Some internet service providers do put a cap on bandwidth. Unfortunately many of them don't tell you this until you are way over on usage.
Living out in the country we don't get any kind of cable/DSL service. We first had unlimited dial-up (cheap but frustrating), then wireless broadband from at&t (expensive and still somewhat frustrating) and we now have high speed wireless from our local electric cooperative. It is great and although it's a little pricey it's well worth it!