I have seen that most credit cards will offer 12-18 months 0% APR on purchases and balance transfers when you first sign up for the card. After that if you want to transfer a balance you will usually have to pay a 3% fee on the balance of the transfer with 0% APR for a year or so.
Do you think it would be possible to cancel your card, wait a little while, and just reopen one of the cards to get the introductory 0% on all purchases and balance transfers? (I'm trying to avoid paying any kind of percentage on a balance transfer that I have been kicking from card to card for a couple of years...)
Probably not. Once you cancel a card it's cancelled. You would have to open a new account which should qualify for the 0% but it would show as an additional credit account on your credit report which could hurt your credit score.