Ivan I think it would be advisable to find at least one payment method for technically less capable customers I know it's very hard and I fully realize it but I would also like it to make it easier for you to make your software as widely as possible
I would first confirm if it can make international purchases before getting one. Not all pre-paid visa allows over seas purchases so the before telling them you need to tell them to make sure it can be used as such otherwise they are wasting their money.If your in the US get a pre-paid Visa from Walmart and your troubles are over, If your not in the US then talk to ppl in Europe or wherever your from. Then you don't even have to worry about bitcoin and all that music.
I would first confirm if it can make international purchases before getting one. Not all pre-paid visa allows over seas purchases so the before telling them you need to tell them to make sure it can be used as such otherwise they are wasting their money.