Usually the most difficult component to get written acknowledgement and agreement on, the financial responsibilities generally should be settled before project work begins. Estimated expenditures, time and material vs. fixed bid, overruns and changes should be explicitly addressed. If the project involves discrete legal parties, this section may refer to a pricing schedule document or other legal contracts.
Obviously, the larger the project and larger the dollars involved, the more critical this section becomes; especially, again, when the project involves multiple legal entities.
Even if the project agreement is between departments in the same company, this section must not be overlooked. If it is not appropriate to list the estimated cost and source of funding here, it must be referenced in the General Assumptions or Customer Responsibility sections. In a worst case scenario, include an assumption that the department heads will agree on the financial responsibilities.