In doing some quick internet research (yes, lawyers find things out that way too), CA has a convoluted redemption process.
If the foreclosure has already occurred, bottom line, you need to pay the FULL, unpaid balance of the loan plus costs. Where things get messy in CA is how long you have to do it. From what I found, if the lender made a full price bid, you have 3 months. If there is a deficiency balance, then the redemption is not available.
However, if you are interested, you should talk to a CA real estate agent. But, be practical for a minute, if you have the ability to redeem, why didn't you just pay to stop the foreclosure.