This could be more than offset by the Property Taxes, depending upon the month that you close:
December would be ideal, as they only collect 1 month's taxes; however, that is probably an unrealistic timeline in your case.
January flips the situation to mean 5 month's taxes.
If the Closing Costs are a "deal breaker" for you, I suggest you contact your Title Company, and have them run a dummy HUD1 to give you a better idea of what you're up against.
Good luck and may God bless
Both Sally and Lance are dead-on with their comments. The 3% value I provided is extremely conservative and depends on the County (and possibly the city) the property is in and what your purchase contract states.
Here is the customary "who pays what" for California: http://docs.Steven-Anthony.com/ClosingCostsGuide.pdf
As Lance points out, if you want accuracy contact your local escrow/title company for a quote (highly advise you do this), or you can construct your own estimate here: http://ratecalculator.fntg.com/
On a cash deal you have significantly lower closing costs, but they depend upon what the customary split is between buyer and seller in your area. Some places split them, some have the buyer pay, some have the seller. In order to determine exact fees in your area contact a local title company.
Lance King/Owner-Managing Broker
Your Realtor and/or title company closing person would be able to give you a good estimate. You'll have to pay your portion of title insurance (which varies), along with other closing & recording fees. Plus you may need to pay a portion of your taxes up front. Some states require an attorney as well, but I don't think that's common in CA.