Western Union money order. They buy it at a Western Union office and mail it in. I have international customers use registered mail if they feel nervous about a payment being lost. Because Western Union is a US company, you don't have to pay a fee to deposit them in a US bank. It has to be in US dollars, but I think that's the default with Western Union. Some countries I don't accept orders from, though, no matter how they want to pay.
In the UK, we have a service called ukash (.com!) which I reckon would be ideal for you. Basically you place your order online as normal, and using ukash you print off a voucher to take to your participating local newsagent/ 7-11 etc... They then scan it and the payment goes through and after about 15minutes the merchant receives notification. Its a great concept for those who cannot get a credit or debit card due to circumstances/ age.