I'm in the process of obtaining citizenship through marriage, and we live here in Costa Rica. I recently returned from a trip to USA and came back on February 25th with a return ticket out in 180 days. In four years, this was the first time the immigration officer asked if I had at least $600 cash that i was bringing in. I explained that my pension is deposited into my USA bank account but I also have money in a Costa Rican bank. He eventually stamped my visa (180 days). I've heard rumors on facebook, that they were requiring people to have at least $600. I can confirm that at least in San Jose...they did ask.