I NEED AN INVESTMENT GURU OR FINANACIAL EXPERT TO ANSWER THIS
QUESTION. THE QUESTION IS: WHAT KIND OF INVESTMENT OR BUSINESS CAN I
START WITH $500 THAT WILL GIVE ME RETURN ON INVESTMENT OF 100% IN ONE
MONTH IN LOS ANGELES OR ANYWHERE IN THE US.

How much time do you have to put into it?
What are your skills, areas of knowledge, and resources?
What do you enjoy doing?

To:daytrader_7__6-ga 
Answers for your questions : (1) I can put in at least 3 hrs/day (2)On
skills consider somebody with a 1st degree in  liberal Arts (3) I
enjoy figuring out a smart way to make money legally with the minimum
risks

I sincerely doubt that there is any investment that can be guaranteed
to double your money in one month. Investment involves risk. IMHO, the
only "sure thing" where money is concerned is that you can't take it
with you when you die.

The roi is not unreasonable, because it does not factor in your time.
3 hours x 30 days = 90 hours.  You only have to make $5-6 an hour.

But what to do?  You will almost certainly make more money at a second job.

I wish I could be of more help.  Whatever you do, be wary of
"purchasing" a business opportunity.

Get a stable of hoes and pimp em out. Big money maker!