Quota

Quota module allows administrator to limit maximum number of nodes of each content type a user can create. The module takes into account either all or only unpublished nodes. This can be useful to limit a user activity until his new nodes are moderated and published. If a user reaches the node creation limit he can still access node add form page without access denied error. However the warning message "Node creation disabled. You reached maximum number of @type nodes — @quota." will be shown instead of a form.

Quota node limits can be set in Quota fieldset on a content type edit page - Administration » Structure » Content types » Your Content type. Optionally a warning message can be set on a node add form for users which didn't reach the quota limit.

The module also defines a self-explanatory "bypass quota limit" permission.