Never Enough Money...
Ok, so you are going to tell me that your client says that all the requirements of the project are necessary and that you cannot cut the scope to save money. Really? That would make your project really unusual, since many studies have proven that on average only 20% of functionality built for end users actually gets used. So figure out what is really needed, convince him that gold plating your requirements is expensive and a poor use of capital. Then give your client back some of his money, and keep the rest for shoring up other parts of your project that need additional resources.