Does anyone know how this works for shipping? I'm selling something and the purchaser tell me he will send a usps money order. He tells me that I will not recieve the money until he recieves the package. I looked on the USPS website and did not find any information concerning this type of money order. All of them are pretty standard as far as he pays for one and I just cash. There is not a whole process of recieving payment. If anyone can help, it would be great.