For example, if I do S/P top stocks, I could get around 11%. but if I did real estate and I have a 800 credit score - could I do real estate and make it work harder doing turn key Multifamily. 

Tyler,Within my 20 years of experience as a landlord, if I had $150k and good credit, I’d focus on either flips for fast capital or rentals for long-term cash flow—trying both at once can slow you down.

You could also get a line of credit for about $150k (you should be able to borrow 75% of the value.)The reason I suggest this is…1) you save $40-$60k in selling costs. 2) you have a lower blended interest rate (2/3rds at 3.25% and 1/3rd at 7 or 8% instead of the whole $500k at 7 or 8%) saving you another $1k/mo in interest. 3) you only pay interest on that $150k when you actually use it, not from day 1  Unless you hate this property, or want to buy something you can’t afford without selling, that would be my plan.

At the moment with 3 rentals (6 total units), I have one account and a credit card associated with it.

The buyer representation agreement states that the buyer commission amount offered by the seller (usually 2% to 3%) is credited/refunded to the buyer.

In neighborhoods that won't attract high credit score tenants, I've found that a stable job history with a MINIMUM of 1 year at current or previous job to be the best indicator of a great tenant. 

Ask for a line of credit.  

intrest free credit cards and cash How did you add value to the deal?

Quote from @Jaycee Greene: Assuming you pay asking price, I'd estimate the down payment for something like that using a hard money loan (HML) would be around 40% of the purchase price and your monthly payment would be $2,600 with an interest rate in the low 7% range (probably need a 700+ credit score to get that).

More on DSCR loans in case helpful: DSCR loans won't use your income to underwrite the loan.DSCR loans are based off of down payment, credit score and either actual or market rents so it helps to supercharge an investor's real estate goals and net worth.