Greetings foreign visitors! I’m sure that the pull of cheap Dollars is making you excited to come and visit the US.

But what if you plan to come to the States and make a lot of mobile phone calls? Prepaid phone service is nowhere near as advanced as it is in the rest of the world, but if you know where to look, you can still find some decent options.

Here are 11 simple things you need to know about our prepaid services, where to find them, and how to save some money.

1) Finding a prepaid sim

The prepaid “sim pack” is impossible to find in the US. No retail stores carry a “sim only” prepaid kit. If you are just looking for a cheap sim card for your existing (unlocked) phone, then you’ll need either purchase a kit with a phone, or visit one of the AT&T or T-mobile branded corporate stores. Even the phone kiosk in the local shopping mall won’t always be able to activate one of their sim cards for prepaid service.

Don’t bother looking around the airport for a prepaid kit. Some common stores that carry prepaid phones are:

• Walgreens, CVS, Rite Aid and most other chain pharmacies (drug stores)
• Bestbuy, Circuit City, Radio Shack and Fry’s (all large electronics stores)
• Walmart, Target, K-Mart (department stores)
• T-mobile and AT&T corporate owned stores
• 7-Eleven and some other convenience stores

2) Beware of non GSM phones!

Virtually everyone in the world uses the GSM system. But in the US we have several different network technologies. GSM is used by T-mobile and AT&T, but Sprint and Verizon use CDMA.

CDMA is also used by many of the virtual operators like Virgin Mobile, Helio, Tracfone and Boost Mobile (who actually use another system, but I’ll spare you the details on that).

There is nothing wrong with the CDMA system, but since it does not use sim cards, you won’t be able to buy a CDMA prepaid phone and put the sim card in your own phone. The CDMA phone will also be useless outside the US so forget any chances of bringing it home and unlocking it.

3) Personal information

When you signup for certain prepaid plans, the store may ask for your personal details. This isn’t for a credit check, it’s just for their invoicing system, as well as setting up a way to restore your service should you ever lose your phone.

If they insist on gathering your information, I suggest just giving them your hotel address, don’t bother trying to get them to enter your home address abroad as their systems don’t take too well to that.

4) Calling abroad on your prepaid phone can be expensive!

T-mobile prepaid is horribly expensive. You’ll be paying $1.60 per minute for calls to most countries. I highly suggest getting a calling card and making international calls through that. Calling cards are available almost everywhere, but I suggest sticking with reliable brands like AT&T or MCI.

Avoid calling cards that promise insanely low rates, as they often add on hidden fees or expiration dates. The average rate for calls to Europe with a calling card is about 10 cents per minute though some calling card services like Nobelcom have rates as low as 1.2 cents per minute.

Of the large prepaid services, only Virgin Mobile has standard affordable international rates. There are several new companies entering the prepaid market, including Tuyo, but they are in my opinion too new, and too small to be able to recommend just yet.

5) Incoming calls cost you too!

The US is one of the only countries in the world where the called party pays for the incoming call on their mobile. If you receive a call, and talk for 10 minutes, you’ll lose 10 minutes of your call credit.

The advantage of the “called party pays” system is that your US mobile phone gets a normal local number and not a special mobile phone prefix. Calls to a mobile phone in the US are billed just like any other call, without surcharges.

6) Incoming texts cost you TOO!

If you thought paying for incoming calls was bad, then you’ll be really annoyed at this one; you pay for incoming text messages too! On T-mobile an incoming SMS message costs 5 cents (10 cents to send), Virgin charge 10 cents for incoming and outgoing and on AT&T you’ll pay 15 cents for anything sent or received. Sending international text messages is also more expensive; 35 cents on T-mobile and 25 cents on AT&T.

7) Add-ons are your friend

Both T-mobile and AT&T offer several versions of their prepaid plans, as well as add-on features.

On T-mobile, a $1 per day access fee lowers your per-minute rate to 10 cents, and even adds unlimited nightly calls from 7pm to 7am. You also get free and unlimited calls to any US T-mobile subscriber. AT&T has a similar option; $1 gets the lower rate of 10 cents per minute, as well as free mobile to mobile calls, but they don’t have the unlimited nighttime calling T-mobile offers.

AT&T also offer an international add-on feature; their WorldConnect plan costs $3.99 a day, but lowers international calls from $1.69 to as little as 8 cents (using the UK as an example). The WorldConnect plan can only be added to “pick your plan” AT&T Prepaid phones.

Both T-mobile and AT&T only charge you for this add-on, on days you actually use the phone, so if you keep your phone off, you won’t be charged the Dollar.

8 ) The more you add, the more you get

This one makes a lot of sense; the more you pay the operator, the more they will give you, but it really adds up.

On T-mobile, a $10 prepaid card is only good for 30 minutes (30 cents per minute), but a $100 card adds 1000 minutes.

So, pick your top-up card wisely, and invest in the largest block of minutes you can afford or think you’ll need. With T-mobile, a $100 card also enrolls you in the “gold rewards” program, which entitles you to a full year of service and a 15% bonus on all future top-ups. The higher the value card, the longer you’ll get service.

Prepaid service does expire, minutes could be gone as soon as 30 days from the time you added them, so don’t be surprised if your investment in minutes has become worthless next time you come back to the States.

9) Don’t call mobile phones back home

If you want to chat with your friends back home, make sure you call their landline. International calls to mobile numbers are horribly expensive. If they don’t have a landline, tell them to call you back. Calling a foreign mobile number can be as much as 10 times more expensive than a landline in the same country.

10) Quad-band phone required

If you plan to use your own phone with a US prepaid sim card, then you’ll of course need to be sure that it is unlocked. But you’ll also have to make sure it supports the frequencies used here.

AT&T primarily use the GSM850 band, and T-mobile use the GSM1900 band. There are some areas where these providers will use each others towers, so if you want to be sure you’ll get a signal, bring a quad-band phone. A European dual-band phone (GSM900 and 1800) will NOT work in the US.

11) Avoid the mobile phone completely for long calls

If you can’t sleep without talking to your girlfriend for an hour every night, then you might want to consider finding a cheaper way of chatting. Mobile phones are great for the occasional chat. Consider using Skype, or one of the many other Internet calling applications. If you don’t want to drag your laptop along with you, then consider one of the Skype Wi-Fi phones.