That was my post. Single license. No group licenses with CoStar. No multiple users on one license. Each person in an office reasonably likely to be a user needs a license.
Fool around trying to get around their licensing requirements and you have a good probability of being sued by them. And, if so, you have a good probability of losing. If you can't handle the fees, you surely can't handle the judgment.
If you need the service, it is a bargain at twice the price. CoStar is a relationship that needs to be managed like any other vendor or client relationship. If you don't invest in the relationship, you are going to have an unpleasant experience with CoStar. I make the investment and my office has a productive low-stress relationship with CoStar. The appraisers who hate CoStar, IME, are unskilled salesmen. They focus on every factor except what is important: if you need CoStar, you have no relocation threat. Focus on that like a skilled salesman would, and the path to relationship management is obvious. Complaining about CoStar is a visible indicator of a lack of skills.