Hi JJarmuth07 and welcome to the AccorHotels forum. As a accorhotels member you should receive a better rate than non members. AccorHotels runs several sales during the year - but as you plan to head back fairly soon, you may not hit the sales in time.
The system does not allow for codes input - so non that I am aware of. They do however work with some of the cashback sites where you often receive at least 10% back (tracking and confirmation takes some time though).