I know that you can do SharePoint Site Collection Quotas out of the box, but what about Individual Site Quotas? I seem to remember a third party utility that can do this, but Google turned up zero on this. Thanks!
The site collection quotas actually setup a quota for each site in the collection. So if for example you want to limit a site to 100mb and warn at 90mb, that happens on each site in the collection, not for the entire site collection.
If what you are looking for though is, within a site collection, to say that Site A's quota is 50mb, Site B's is 100mb, and Site C's is 200mb - then you do indeed need a third-party utility.
The only one I know of is not free (and I haven't ever used it), but here is the link: http://sharepointgovernancekit.com/