@Yang Zeng Welcome to the Bigger Pockets.As you can see in my profile, my business and hub is in San Diego, not far from you, but all our investments for myself and my clients are in well performing markets in the Midwest.We specially in this out-of-state- approach that really requires more than just the properties.I agree that you should keep a reserve and not spend all your funds but I could help you with 6 properties that would pay you about $5K/ month in cash flow or $60K/year based on your available funds while having about $100K reserve.I like to help you see the performance difference between our area in CA and the Midwest.

If someone doesn't have enough cash reserves, they shouldn't buy RE but focus on saving up money, increasing current income and paying down existing debt. 

It is still the seller's debt and it remains their responsibility.

Different investors swear by different criteria, whether it's IRR (and the closely related NPV), cash on cash, the debt coverage service ratio (DSCR), the CAP rate for a property, or some other metric.

Todays 30 year fixed rate mortgages are an astonishing 7.1% Based off that I am finding a lot of properties that, if at a 3.5% interest rate, would have a great 9% C on C return.

Southern California is a tough market,  however, its doable based on our experience. 

I am a New York based new-ish investor working to expand. 

Sounds like prices vary based on each situation but I'm looking at $15k.  

I'm not sure of the regs but I moved some money from my Trad IRA and Roth to SDIRA's years ago.The fees are largely based on transactions not asset value. 

Are there other markets I should consider based on my criteria?