Years ago I asked that they let me buy a SIM card in the airport arrivals area and now they often do. I also started a forum here on the best company to buy a prepaid SIM from in each country which has a fair bit of traffic.

And indeed, I have been doing that, because often roaming rates remain obscene. I dropped my Canadian SIM when Sprint offered a plan with 20 cent/minute roaming in Canada that I can turn on for $3/month -- this was comparable to the prepaid price I was getting, and prepaid had the "overhang balance" problem I will discuss below. But I've gotten or been loaned local SIMs in several countries to good use -- especially when both I and my travel companion have one so we can use our cell phones as radios.

But a few problems exist with getting a local SIM. First, you have to get one. The cheapest place to do this is usually the local cell phone shops that can be found in most urban shopping areas. If you plan ahead, you can get one mailed to your hotel, though the companies that do this which aim at tourists always overcharge -- perhaps enough to wipe out your savings if your call volume is modest or your stay short. The ideal SIM is near-free, and can be found where you enter the country.

Next, you must fill the account. Almost everywhere, you must use prepaid cards bought for cash from the shops, as they will not let you fill, or refill, with an out-of-country credit card, for supposed security reasons. This is annoying because you don't want to have a large balance remaining (overhang) on your prepaid account when you leave the country, unless you will be back before it expires. (Sometimes you can use it up in other countries with obscene roaming rates, but often not even then.) But you also don't want to have to risk running out of minutes in the middle of a call.

The answer: Let me put a fat balance on my prepaid account, and let me refund all or most of it when I am done -- ideally back to my credit card when I leave.

The cell company loses that wasted balance, sure, but instead, I am prone to use the phone more if I have a large enough balance and a good enough rate that I don't have to worry. I will use it like a local. This would be a good competitive edge that would make the difference if I were buying a SIM. You could offer this only to people from out of the country but I see no reason not to offer it to local users too.

Yes, processing the refund has a small cost. If you insist, don't refund the last few bucks to cover your costs. Or alternately, let me do "minutes transfer" to other prepaid users. Then I could meet somebody (or go into a shop) and transfer the minutes and get cash for them.

Of course, it would also be nice if you would let me just buy a monthly plan deal for just one month, with no contract. Cell companies seem loathe to do this, but T-Mobile in the USA has just started doing exactly that with their flex-pay. In that system you pre-pay for one month of any monthly plan, and if you think you will use more than the minutes on that plan, you can put money into an overage account. But you can't get it back, so that's one modification to add. But frankly I would probably never go over the monthly plan I bought in a typical trip.

The remaining big headache is data. Getting a prepaid plan with data at a decent price (or any data at all) can be hard. Those from the USA are used to unlimited data, which they resist selling in many countries. Those from the USA who bring their phones overseas and forget to turn off roaming data often find nightmare bills of many thousands of dollars. The world has to figure this out. Still, those who are used to fancy network PDA phones often find themselves literally lost without their Google Maps Mobile or their e-Mail. We need a way to roam data selectively, letting some apps use limited data budgets but preventing others if we can't get a decent data price plan. E-mail apps can go into low-data move (never download attachments or long messages automatically, just imap headers) and less frequent checking. If one is careful, one can get something decent at the $2/megabyte (or $10/megabyte) crazy prices for mobile data roaming.

Oh yeah, and think about doing 2-SIM offers to tourists, who often arrive in pairs. Especially if they include cheap mobile-to-mobile calling in the pair.