well it goes like this:
you need to call a foreign country so you buy a card....
the cards usually sell for less than the marked price - so you buy £5 credit for £2.50 or £3, each different brand has different rates for different destinations, which are marked on posters which are usually not accurate, so you ask the vendor:
"which card for abu dhabi please" for example.
the economics of the calls, as far as i know works on 'callback' technology, so the producers of the cards have virtual switchboards that connect yr call via whichever network is cheapest - i.e. cheaper to call from the US to UK than vice versa,
however,
that's not how the card producers make their money, they rake off any remaining credit when the card expires after a month, or by shutting down their switchboard after selling lots of cards which then go defunct,
zero chance of refund for the buyer as the vendor is not liable (or is liable to tell you to feck off)
so that is the only part which is at all a scam, but as the buyer of the card is losing only pence or a couple of quid max it's no bother really, especially as it's way cheaper than callshops, bt or the mobile networks,
& the other obvious advantage for the user is that you don't need any sort of an account.
thus; the card which you spent £3.50 for £5 credit giving you 110 minutes to antananarivo last week may be sold at £2.50 for the same £5 credit but only 40 minutes talktime to the same destination next week...
that is why the vendor is your best guide to where the value lies,
i have used them many many times and never had a bad card,
while it is not a transparent system, or one that is covered by any national or international laws regulations etc, it works, partly because the trade is structured in a way that removes incentives for anybody ripping off anybody else, especially at the street level where the transaction between buyer and vendor takes place,
i guess the vendors are getting the cards wholesale, on credit, sale or return, so it's an easy business to start up, i think the margin for the vendor is probably about 5p per card so overheads need to be kept to the barest minimum,
(selling poor quality accessories at sub-99p shop prices is a sideline)
(there is another slightly more dodgy version where you get a number that you call at a premium rate that is still way cheaper than standard international calls - these are apparently using hacked corporate switchboards so are very fly-by-night, but tiptop value for money. but i think reputable card vendors don't touch these)
the decor and naming of the cards are often shining and delightful examples of ephemeral carefree vernacular design - there's a 'phonecard kiosks i have known' photo essay to be produced on these tiniest most colourful businesses
?claro?
