look at Hertz.co.uk
Every CDP gives a specific rate for the same service .
using a Amex FB cdp 769269 and PC 192021 on your dates in ORD you' ll rent a full size for 218.63 USD and take any car you like .
I understand that for someone from a socialist country it might be hard to understand but its a free market and " prize " is in the world of car rentals exactly the same as is in the world of advertisement sales