Just a matter of doing the math.
1 Mbps = 1,000,000 bits/sec = 125,000 bytes/second
= 122.07 Kbytes/second
= 7,324.22 Kbytes/minute
= 7.15 Megabytes/minute
= 429.15 MBytes/hour
=10,299 MBytes/day
= 10.06 Gigabytes/day
= 301.75 Gigabytes/month [in a 30 day month]
Multiply that by 10 for 10 Mbps, and that's 3000 Gigabytes/month, or 3 TB (terabytes)/month for a 10 Mbps connection, if it's fully saturated the entire month.
Of course, normal sites have peaks and valleys. With an unmetered connection, your "peak" can't go higher than what you pay for. If you want things to be "burstable" above 10 Mbps, you'd pay more.
See ev1servers at:
http://www.ev1servers.net/Dedicated/10Mbps.aspx http://www.ev1servers.net/Dedicated/100Mbps.aspx
although there are lots of other hosts that offer unmetered bandwidth, if you search around the usual hosting forums.