TenderRoad has a free tier so you can see the quality of the matching before paying anything. Free accounts get matched contracts and a weekly digest.
Paid plans add unlimited matched contracts, morning alerts when a high-scoring contract is published, full bid qualification scoring with the reasoning behind each verdict, deadline reminders, buyer profiles listing the current and past contracts of each buyer, and alerts for new contracts from buyers you have bid with before.
Plans are monthly or annual with no minimum term. Compared with the cost of a single wasted bid, or the cost of missing a contract you would have won, the maths tends to be straightforward.