Geo-coding services

   I need to geocode 720K property listings by next monday,  I've already started with a couple free services and one company that charges 20$/20,000 TRX but I need more but if I rely on that, I figure I'd pay 1,300-1,600 dollars at the end of it.

Anyone know anything else out there for getting the lat/long coords of an address in the USA?