you have 500 visitors and you demand for best, first of all you need to check if you can be even accepted in most ad network usually big guys do not even accept sites less than 5000 daily unique or your best option is may be google adsense as they do not ask for number of visitors only website should have good content I really feel though you need work on getting more traffic no matter whichever network you may get accepted or try you will be disappointed because 500 visitors is nothing to earn money By the way I am hearing good review about edomz cpm and they are accepting I think now more members so you should give it a try
From the way it reads he is looking for 500k per day, but it looks like you are a bit smaller than that, you are welcome to register and test our PPC Network
I think you are asking payment? We pay our publishers monthly via ACH or Paypal with a $50 minimum balance. Our advertisers pre pay by credit card. For publishers that earn more than $1000 per month we have an early withdrawal system.
you have 500 visitors and you are in search of best ppc networks, first you need to think with that kinda of traffic best network even want to accept you no premium network accept less traffic websites so just try to get into adsense or with that I doubt you can get into best network like valuclick media or others