How do i pick a realtor for new construction townhome?

[Sreenidhi S.]

Im about to put 3% down to book a townhome is milpitas. i haven't visited the physical site yet but got on their priority list through their web site.  I want to get back as much money as possible so im thinking of going with redfin or some other realtor who can give 1-2 % back. I'm assuming this strategy should work fine because any realtor wont be able to negotiate price down with the builder (who will go with the next person on the list if im not happy with the price) 

Since I'm already on their priority list, can the builder refuse to pay buyers agent commission?