To add to that: I can buy wholesale bandwidth within Europe with some ease for <$2 per TB transferred. If you look at quotes for undifferentiated transit from pure bandwidth providers it will be higher, as they typically price based on global routing, but when you know your breakdown is heavily tilted within a region, you can get massive discounts by e.g. limiting 95% or whatever of your capacity between European networks where the provider will exchange most of the traffic via peering - of course the big carriers do their own peering and own their own networks and effectively pay event less.

But even the most price-gouging "captive audience" transit providers (e.g. in data centres without multiple choices of carriers) rarely charge more than ~$10/Mbps (depending on utilisation down to ~$40 per TB transferred or about 0.04 cents per GB...)