Gary mentioned in his blog, you can get $35 off and 1700 BMI miles for a one day weenend rental. This is the best deal for a one day rental. use coupon code 121365
Deal for 2 days rental is Delta 3000 bonus miles with Budget.
Deal for 3 days or more is Delta 4000 bonus miles with Budget.
Deal for 4 days or more is Delta 5000 bonus miles with Avis