Unmetered bandwidth hosting means that the hosting provider will not monitor or keep track how much bandwidth you already used up and how many remains for the month. Usually in cpanel control panel, you can see the bandwidth usage indicator on the left column. That's the tracking of monthly bandwidth.

For unmetered bandwidth hosting, these bandwidth usage is not being tracked and recorded. This also means that you will not hit the bandwidth limits. And you are allow to use as much as you want.

Most the time, shared hosting plan, not only the unmetered bandwidth plan, will have usage limit. This will include the cpu usage limit, thread limits, files limit, mysql connection limits, and so on.

When you shop for unmetered bandwidth hosting, make sure your hosting plan are reasonable price. Usually these plan will cost extra 50%-100% compare to the shared hosting plan with bandwidth limits. Taking example the midphase hosting, their plan details at here http://www.midphasereview.org/midphase/midphase-hosting . Midphase normal shared hosting are price $8, and the unmetered hosting package will cost $13 dollars.

Remember that you are getting what you paid for. And definitely there will not be $3 dollars unmetered bandwith hosting that going to allow you to use all the bandwidth as you like.

Shop wisely, and look for the right hosting plan always!