is it possible to invest in a small apartment building maybe 5-10 units with no money down and still have a positive cash flow or at least a break even somewhere in southern california? if so please explain. Thanks.

try looking up the term master leases or subject to. a creative way of doing this can also be used through a land trust by having the seller assign partial beneficial interest to you. then you either rehab the property, lower the expenses, increase rents, etc to get a better NOI(net operating income) . then refi cash out of the trust at the newly appraised value. try to get the DSCR(debt service coverage ratio) above 1.25 to get better conventional financing.

Not possible in So-cal..You are looking at 20% down just to break even and 35-40% before it makes sense. Most serious investors have gone back east. Dallas, Tulsa and Atlanta are all hot right now.