You can't. Even if you make a pscurahe and get cash back at the time of the pscurahe, it's considered a cash advance. Some cards waive the cash advance fee if you get it at the time of a pscurahe, but you still accrue intereste charges from that point. You would also not be able to get $3000 cash on a credit card with a $3000 credit limit. There is no way around that.