Try to save up for a down payment and use the credit for the rest. That is what I would do if I wanted a Powerbook and didn't have enough credit to buy one. If it cost $3000, I'd save up $1200 and put the $1800 on the credit card and then pay it off. Just take the payments you would have paid the credit card and put them into your savings account. By the time you have enough for a down payment, Apple should have a new Powerbook out on the market with better features and longer battery life. :)
"If you're going to cheat, cheat fair. If there's anything I hate it's a crooked crook!" -Moe Howard