看见TTY在用Tru Sim，就去它的网上看了一下，http://www.truphone.com/en-GB/Products/ 好象在美国可以免费接收短信
充值后多长时间作废网上没注明，于是给客户服务打电话。被告知：永远不作废，但有一个前提：私人账号不能连续六个月没有动静。
non usage of the sim for 6 months it will automatically be deactivated and the remaining balance will be forfeited. An account maintenance fee of $2 or 3 GBP will be observed. Also what you can do is atleast try to send an sms once in a while so that it will reflect on our end that you are still using the sim lets say in a span of 3 months.
听起来令人难以置信：$30买个卡，含$15充值，并跟来一个电话号码。你就有永远免费接收短信的功能了。在美国费用如下：
Call landlines cost per minute: $ 0.15
Call mobiles cost per minute: $ 0.15
Receive calls cost per minute: $ 0.15
Send a text cost per message: $ 0.10
Receive a text cost per message: FREE
Data per MB: $ 0.15
昨天终于用这个服务打了两个电话，每分钟不是收费$0.15，而是$0.17，多收的$0.02/分钟是税。而且用手机查留言也要按正常通话计时收费。这么看来，除了免费接收短信这个功能，其它都比不上最近坛里网友sailfish发现的Lycamobile：
通话费$0.02/分钟
数据$0.06/MB
短信$0.04/个
用手机查留言不收费！
How much does it cost to access the voicemail?
Your Lycamobile Voicemail service has been automatically activated. To access your voicemail from your Lycamobile in the US dial 121 (or 91#). Calls to access the voicemail are absolutely free.
Does Lycamobile charge taxes on my order?
All charges are inclusive of tax. However, there may be required sales and similar taxes that are required by the state and are charged by the retailer where you purchased your Lycamobile products. There may also be various federal and state fees that Lycamobile must collect or that Lycamobile must pay as part of regulatory requirements that Lycamobile may pass on to its customers.
Lycamobile 的用户有人反映常有垃圾短信，这个比较头痛，每收到一条垃圾短信要花费$0.04。他们的客户服务也没有好的解决办法，不过似乎可以关闭短信功能：
How can I stop receiving unwanted texts or SPAM?
When you receive a text from a company you have not given your number to, this is called SPAM. Unfortunately, Lycamobile is unable to prevent you from receiving these unwanted messages, unless you want to ban all text messaging. These companies have sophisticated ways of obtaining cell phone numbers. One way to avoid SPAM is to be careful about what sites you give your cell number to.
如此看来，两个服务都有最好，用Trusim接收短信，用Lycamobile接/打电话。估计用那些双SIM卡的手机做这个最合适了！
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