API limits

We want to call API to get session_id for particular user before we log subsequent logs via clicky.log manual logging.

That means we need to call API for every user just right after he logs a first request to the site. We can limit result to just 1 row but still its a lot of requests.

At the moment we have about 1 million users per month. Can we call API 1 million times per month?

Thanks,