When a Load Manager doesn't specify a rate in their Load Post. The load list will say "Contact for rate" in place of a dollar value. This just means that Load Manager would like to discuss the rate with your when contacting them about the job details instead of posting the rate publicly.
Tip: Many loads do not specify rates. So when creating Alerts its best to leave "Show contact for rate" checked. So you will still get alerts for post jobs without rates attached.