Fair Commission Compensation for New Construction Broker Co-Op

[James Sun]

What's a fair commission compensation on a new construction broker co-op fee?  Assume that the agent is a broker and no other fees are required for the sale to complete.  I'm interested in seeing opinions on actual dollar amount and not %.  Builder will not lower sales price of new construction property and broker co-op is paid out of their marketing budget.  I'm using the agent/broker strictly to lower my net purchase price and there is no expectation of any additional value add out of the transaction.