in the 80's, there was a period of about 4 months when some cc's were giving purchase credit for balance transfers....

i did tinker to evers to chance [famous baseball double play combo] w/ a mileage card [1/$], a car card [5% toward auto purchase] and a cash back card [1%] for an effective 8% return.[w/miles at 2 cents value].

fortunately, we were booking a lot of high $ travel and i spent about $80 k in the period...