I'll join the bandwagon for knowing the costs up front. Negotiating is a major buzz kill with me, so I never do it. Add to that my agreement with findinit that if it takes more money to loosen things up, they are not really into it, and I don't do well with that either. With everything well defined at the start it could still be a performance on their part, but at least all parties have had a chance to evaluate the risk / reward ratio and come to terms with it in advance.