Is there a limit on amount of US dollars you can take when going to the States?, also is there a cheaper way than Western Union for sending money over to my son.
I don't think so judging by Wikipedia's list of countries that still have exchange controls. I think the customs (white) or immigration (green) forms may ask if you are carrying more than a certain amount in cash (US$10K?). I suspect that WU is far from the cheapest way to send money. What about Paypal?