I plane to start with a bank of $500. Any suggestions on how to generate an income. I'm hoping to double it every 30 days if possible.

I normally back between 3 and 5 horses a race.

If you are currently backing 3-5 horses per race - what is your strike rate and your POT.
Breakdown what you have into what you want and then you have what you need to do.

If your SR is 100% and you make a $1 per race you need 500 races per month. IS your current betting system going to allow you 500 races per month? That's 16 races per day. If not you will have to increase your stake. Is your SR 100%? If not you will have to increase your stake.

If I am reading you correctly, you are asking for an alternative method to generate this income. If so lay. Lay the field all races. It will be a bumpy ride and you may lose your $500 in 2 days. You will lose 4 months in 12 but you will win. My estimate would be $7500 per annum at $30 liability. You could also drop some of the field, restrict the fieldsize and the minimum price range.
Why have I given this? Because you won't do it. The first bad run and you will stop. $30 min liability will do that. If you could start with $1 everybody would be doing it.

my s/r is around 63% for 3 horses vin a race uo to 84% for 5 horses. My proit is around $10 to $ 15 dollars a race

What is your outlay per race?

$100 a race

Benny, unless I am missing something here, you have a LOT.
100 races winning between 63% and 84% backing 3-5 horses to win on average $10-15 per race.
Using averages SR ave 73.5% win $12.5 ave.
100 races outlay @ $100/ race $10000. but you win 73.5% so you are funding 36.5 races outlay $3650.
You win 73.5 races for an average $12.50. Winnings $918.75. Loss $2731.
This is not going to do it.

well if that's the case why did you ask the original question - on the basis of 3-4 races per day you are already doubling your bank in 10 days.

A genius of a scale that we have never seen before.
Don Scott X 100 reincarnated.

LOL

Do you expect that statement to be taken seriously.
why don't you whack a few selections up and show us.

Here's the selections for Hatrick (NZ dogs) in rated order

r5

#'s 8.7,2,5,4

My ratings only predict the likely winner

Winner no.5 paying $11.00 on unitab. Plus the tri which payed $106.50

Beton, I was reading your thread "Staggered lay the field", but it stopped abruptly on the 11th of June 2012, without the final chapter being published. Are you currently laying the field using a staggered stake regime or just laying the field or part thereof based on max odds filter? Did you end up laying to liability or fixed bet? Did you fully automate it or take Mark's advice and try and frame a field to achieve better than 90%? Good to hear it's going well for you, if after a year since your original thread, you're advising Benny it's the path to walk down.
Cheers RP