So, for the most part, we always stand on one side of the mirror of domaining. Do you ready to pay end-user prices for your great ideas? Let's discuss this. Personally, I bought one domain for my project in installments.
I've paid end-user prices or near for a couple of names, but I always look for a great deal -- I factor in the likelihood I could resell the name in five years for as much as I paid if things don't pan out.
Unless the name is with HD/BuyDomains/Namefind, I'll always try to reach out directly and negotiate, ignoring the marketplace listings.
Would probably never work with a broker to acquire something for my own development purposes, though.