Big companies lease dedicated lines from the telecom giants, like Verizon and AT&T. My company (25,000+ employees worldwide, with multiple locations across the United States alone) leases several T3 lines from AT&T. Last time I heard, our monthly charges for that were well above $300,000...but when you're making billions annually, that's a pittance.
Schools can get access to the Abeline (Internet2) network, but that's dedicated for certain uses, like transmitting massive files between schools for graduate work or research. On a campus that has access to Internet2, students usually are not just wontonly allowed to use that network...
You more or less can't "own" bandwith. If you want to run your own server, either get cheap hosting and deal with bandwidth limitations, or find somewhere (e.g. if you live on a college campus) you can leech bandwidth from and host a server - but be prepared to deal with the consequences if it turns out you're violating whatever TOS or policy that comes with that network connection.