1 The average car rental price will fall in the range of $20-$200 per day. 2  Budget offers a standard four-door sedan for about $100 per day. 3  The length of time the car will be rented as well as the type of car can also affect the price of car rentals.4  Hertz.com offers monthly car rates at different prices. Hertz.com offers monthly car rates at different prices. 2  They have a wide selection of vehicles, which can cost from $675 to $2500 per month. 3  Thrifty.com also provides car rental services. 4  They offer different packages such as daily, weekly and monthly rentals.