Transfer your other Visa/Mastercard Cash Cards to Amazon!
I used this to add the amount that I had on a Visa gift card that I received last year.  What I wanted to get on Amazon was more than the amount on my gift card so I felt stuck.  Googling is seemed that the best method was to reload my gift card balance using the Visa, and then at Amazon checkout I could apply my giftcard balance and then supplement with other payment means.  Sneaky sneaky!
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