有亲戚从中国来，见本坛有人谈论Lycamobile（忘了第一个是谁了），费用低廉，就也去弄来试试.
website: http://www.lycamobile.us/en/
step 1: order free SIM card (the standard-sized SIM card has pre-cut lines and can be bent into a micro sized SIM card)
step 2: insert SIM card into an unlocked GSM phone (retired T-mobile phone, for example)
step 3: register the card and obtain a phone number. Your login is your 11 digit US Lycamobile phone number. Beware the login starts with 0 instead of 1 (e.g, (514) 678-9012 => 05146789012).
step 4: top-up the account. It is interesting that you can add ANY amount you would like by selecting "other" amount (I did $2).
step 5 (optional): you may want to set auto recharge (when the balance dip bellow X, recharge Y)
And you are ready to go!
我用的是Pay As You Go所以只说Pay As You Go rate
优点: SIM卡免费，最低充值任选（不喜欢权当今天没写网评，丢了5毛），能自动充值，接收通话每份钟2美分，拨打美国通话每份钟2美分，接收短信免费，发美国短信每个4美分分，拨打加拿大、中国通话每份钟3美分
缺点：别人在你语音信箱留言要算分钟（听留言不算分钟），接收短信时Caller-ID不对，据说800电话打不通【但我试了18884242424，能打通】。数据好像不便宜。
Lycamobile据说用T-Mobile网，也有数据（Pay As You Go 6c/MB）。我给亲戚用的是老旧T-mobile手机，不能上网，所以没测数据使用情况。
结论：亲戚朋友短期访美给置个Lycamobile手机非常廉价，有旧手机的话$0.50（其实无最低限制）就能启用，分钟费用可能也是最低的之一。能自动充值。充值不过期（但120天不用就作废--只要用一次又能维持120天）。
当然蹭Verizon网的能更便宜，但技术要求太高，一般人还是不会。