Khan Academy's Pre-Calculus site can be found at https://www.khanacademy.org/math/precalculus
Coolmath.com has pre-calculus materials including reviews of algebra, geometry, and trigonometry basics needed for pre-calc. The link is http://www.coolmath.com/precalculus-review-calculus-intro.
The Math Page has a list of topics that support pre-calculus classes. The site and the list may be found at http://www.themathpage.com/aprecalc/precalculus.htm
This site from NYU's Courant's Institute of Mathematical Sciences has a resource for single topic handouts and additional practice problems that may be helpful. The URL is http://www.tkiryl.com/precalculus.html
Some video tutorials for Precalculus, are available on Youtube. These are FREE resources. You will probably run into clips and ads for “The Tutor Guy” which looks like a nice resource, but is NOT FREE, so think before you click!
Precalculus 1- Algebra Review.
A series of 82 videos on the algebra involved with dealing with precalculus and more.
https://www.youtube.com/watch?v=W-Zxdsbr0Gw&list=PLX2gX-ftPVXX_bDWBA2qhZE-VFgvZur4d
ProfRobBob’s Precalculus videos on YouTube
Contains 153 individual topic chalkboard talks.
https://www.youtube.com/playlist?list=PL4FB17E5C77DCCE69
Thinkwell Precalculus
Has 8 video sessions on precalculus topics.
https://www.youtube.com/watch?v=x7gPpXwnc_g&list=PLDB11AB8E5DEEF7B5
MORE THAN THE NAME IMPLIES: This series of Youtube videos operate somewhat like Khan Academy's electronic blackboard talks, and covers a wide variety of subjects. It has been found to be useful by several Pre-Calculus students. https://www.youtube.com/channel/UCEWpbFLzoYGPfuWUMFPSaoA
https://www.youtube.com/playlist?list=PL3Ip1JQi4mmI9P7QBzU-x2JFNyqSF2Nfz