I actualy emailed cloudmark about this for our installation that processes 30k emails to pay, and I got a reply saying that it was fine to use thier servers for free. I'd email them and ask.
True, but regardless of what amount of email cloudmark is OK with you doing for free, you cannot run a local razor server for free. That's a for-pay option only.
Since the OP wanted to run a local razor server, I was stating that would not be possible with the free client.
As for doing 500k/day for free, yeah, you can ask cloudmark. However, I think the network load on your end might kill you without a local server when pushing 500k/day.
