You can make a free account in order to upload your own creations as well as use some of the more advanced features. If you are looking for a one-stop-shop to pick up some CC to get you started then TSR is worth a visit.

It contains a search function and filters as well as a huge range of curated artists, whose work is exceptional. The Sims Resource, or TSR as it's more commonly known, is a huge catalog of custom content.