1. The value of the coupon is usually not calculated in the rate that you're given online. You may see something that states this (in small print, of course!) on your rate quote page. This is because:

2. The value of the coupon will not be subtracted from your total price until the end of the rental. You must meet the terms and conditions of the rental before the coupon is determined to be valid. This will be decided based on what you do on the rental, not what you say you will do on the reservation.

(Example: Say the coupon is for a free weekend day that requires a 3 day minimum rental with a saturday night overstay and a return by noon on a Monday. You pick up the car on Friday morning, surrending the coupon and based on what you've said you'll do (you've reserved the car from Friday to Monday) the coupon is valid. But let's say that your airline cancels your flight on Monday and you're not able to return the car until you fly out on Tuesday morning.

Although you would have met the three day minimum requirement and the Saturday night overstay requirement, by not returning on a Monday, the coupon would be invalid and no longer applicable to your rental.

Assuming that you've met all the terms and conditions of the Avis free day coupon, you can caluculate the rate reduction by looking at the quote that you get from Avis. If you are given a quote of $79.96 base rate for let's say 4 days, and the taxes and surcharges are $38 you'll be shown an approximate total of $117.96 To calculate the car rental coupons value, just divide your base rate before taxes by the number of days of the rental. (the coupon applies to the base rate only; you still have to pay the taxes and surcharges on the "free" day.

$79.96/4 = $19.99 per day

So you would take your total quote of $117.96 and subtract $19.99 to come out with a new rate of $97.97 -- this is what you would owe at the end of your rental - again, assuming all terms and conditions of the Avis free day coupon were met!

Hope this helps!