A lot of online and mobile services can be paid for through paper vouchers that can be bought with cash at real life shops. Many phone networks issue their own vouchers, as do companies as diverse as Skype and Habbo.
Should Nokia bring out some kind of voucher system so that people can buy N-Gage games with cash?
Such vouchers could potentially also be used to pay for Nokia's other services such as its Nokia Music Store and Nokia Maps, so this concept goes beyond just games.
I can't pay for N-Gage games at this moment, because they have not left any option for me. I don't have a credit card (and I won't have one very soon), and operator payment is not possible in India. I would surely welcome some voucher system, provided Nokia implements it here.
Just out of interest, which country do you live in Sandy?
EDIT: (D'oh! Sorry, you already said you were in India! Yeah, vouchers sound like a really good idea for India if phone bill payment isn't possible at all there.)
It would also be great way of buying games for other people (e.g. to do give aways on AAN for example).