your parents can go to the bank and show them your I-20 and make a cashier's check which they can send it to you. i doubted anybody will exchanged money like you proposed unless there is a significant cut on the exchange rate. there is also a risk to transfer money to a stranger in the US. for example, if i send you money and you do some illegal stuff and get caught, that money will create a link between you and I . good luck.