I find it amazing that using a 50% off certificate requires you to pay tax on the savings. Is there any other business that offers you a coupon and then taxes you to death when using it?

I just used 3 * 1/2 free day coupons and because I used the coupons, the rate was increased, such that I ended up paying $45 for the two day rental out-of-pocket for a mid-size car (1/2 day + taxes).

I probably could have paid a discounted $35 a day for the car had I not used the certs ($35+35+15 tax=$85), so each certificate is probably only worth $10-15 because you have to pay taxes on the much higher rate.