Where I work we have an SDSL line, 10Mbit up/down, with the bandwidth being charged by the 95th percentile of sustained 3Mbits/sec...it comes out to a fairly reasonable number, similar to about 20-25 consumer DSL Lines...we will be changing that for fibre, same bandwidth, almost the same price...

T1's and other leased lines are too expensive...check for SDSL offerings in your area

Granted, my office is in downtown of a large city, so we have more choices...