In April of this year I applied for and was approved for the Barclay card. I chose to apply for this due to me needing a new laptop before my fall semester of college begins. However, I wanted to wait until WWDC when the new laptops were announced before I went ahead and purchased one. As ignorant as this sounds, I just now read that the 0% interest rate for 18 months only applies within the first 30 days of the account being opened. My question is: Seeing as I am well beyond my first 30 days of having an account open, will me purchasing a MacBook Air "today" cause my monthly payments to instantly add on the 22% interest rate? Or is this interest rate added on only after my first late payment? I'm not worried about paying on time at all. My worry is that I'm going to buy this $1300 MBA and I'll instantly have a 22% interest rate attached to the payments. This seems pretty ridiculous in my mind, but I'm not sure if this is how they work. I'm new to owning a credit card and I definitely don't want to pay 22% extra for a laptop when I'm planning on paying every month on time. Thanks for reading. Advice/answers are appreciated.