paypal is free and then we don't have to enter our sensitive information to another party, besides cash can get lost or stolen in the mail, and money orders can be faked. it is free to get an account, and the money you get can be transferred directly into your debit card or credit card or bank account that you used to pay the shipping with. They also send you a free paypal mastercard so you can use it like a prepaid card anywhere mastercard is accepted. it is the only "safe" way for both seller and buyer to transfer money because the money is transferred immediately.