I've never used an interest free card before. This is for the Amazon card: http://www.amazon.com/gp/cobrandcard...A1K78YP8HAIQ2W I'm looking at a $10,000 order on Amazon for various photo equipment that I would like to space out over 12 months, interest free. Is the 0% APR only for that one initial purchase, or is it for any purchases made on the card within the first year? I want to buy about $7,000 initially and $3,000 later on. Is only the $7K interest free of the $3K? "For each promotion, if the promotional balance is not paid in full within the promotional period, interest will be imposed from the date of purchase at the variable Purchase APR that applies to your account when the promotional purchase is made." The "promotional balance" is the balance of that one initial order? Only that amount gets interest free for 12 months? ie. I buy $7K and that becomes the promotional balance and I get no interest on it. The next day I buy $3k but that isn't part of the promotional balance so I should pay off the $3K ASAP. Is that how it works?