Avis - Just found that booking through Fatwallet there is 3% cashback

Good to know

however, there is no cashback for Hertz and national.

An alternative way is to book through hotwire or priceline, but I am just wondering the reservation made through such 3rd parties are still qualified for the promotions such as 2 2day rental and get one free day?

The only bad thing is if you use a discount/promocode/coupon/airline bonus mileage offer that's not listed on the Fatwallet cash back page, the terms and conditions state you will invalidate your cashback. :(