Alaska has multiple carriers and I think you might be in a disadvantage using prepaid over contract because of the reduced roaming. I can see you are from Israel and don't know whether you are also a U.S. citizen (which is a common pattern). If you are or otherwise U.S. credit, you might be better with a month-to-month contract from a carrier that offers those. I know that if you don't need the equipment subsidy, these are available for Verizon and ATT. You need someone who'll have roaming agreements with some of the very small carriers. Otherwise, I'd go with this:
http://www.gci.com/wireless/plans/fastphone