Multi-Unit purchase from a national homebuilder - Bulk Discount?

[Jeff Slusarz]

Wondering if anyone has experience or insight into what % the purchase of 2 units in a spec development might be worth from a discount perspective?   Some details:

- We're considering the purchase of two units in a single development, both priced between $490-499K

- They have indicated they are willing to discount if we don't bring a realtor

- 10 of the 18 homes are sold, with 8 either recently completed or still under construction

They've indicated they are open to providing a discount, but I'm not sure where to start without angering them, but also want to be aggressive.  Given I intend to ask for $15K for no realtor, what is an aggressive, but reasonable offer for the bulk discount?  Is it an additional $25K per unit?  $5K per unit? 

Any advice would be greatly appreciated!!