You might be researching web hosting already. If you started with
the cheapest (shared) then you have probably come across some
AMAZING deals.

You have, without a doubt, came across deals announcing -
UNLIMITED resources for just dollars per month.
The current deal on Hostgator (uber-popular shared host) states:
UNLIMITED web hosting
UNLIMTED bandwidth
UNLIMITED disk space
All for $3.95 a month!!!

Why the heck would you go for any other plan? This is your dream
set up. You can host unlimited sites for a ridiculously low cost.
There is a catch though (isn’t there always?). Any shared hosting
plan claiming unlimited is never unlimited. How could they ever
make their money back? These companies will bury clauses into
their fine print making sure that you can never use up too many of
their resources. If you do...your sites go down. Simple as that.

Hosts do this by limiting things like inodes (inodes store info on files,
folders etc...) or by using unclear statements in there terms of service,
like:
"Bluehost's offering of "unlimited" services is not intended to
allow the actions of a single or few subscribers to unfairly or
adversely impact the experience of other Subscribers."
Bluehost.com reserves the right to limit processor time,
bandwidth, processes, or memory in cases where it is necessary
to prevent negatively impacting other Subscribers
So basically, Bluehost won’t tell you exactly how many resources you
can use, but if it gets to this unspecified level, then they will shut your
site down.

Beware unlimited plans, make sure you read the fine print first....