To ensure that you receive this special advance purchase rate, we will charge your credit card a prepayment of 542.48 USD (your full room charge plus tax) when you make your reservation.
Canceling Your Reservation
You may cancel your reservation for no charge until August 6, 2014 (30 day[s] before arrival).
Please note that your prepayment for this special rate is non-refundable.
Perfectly clear.
(1) You pay upfront in full.
(2) There is no cancelation charge 30 days out
additional to the rate you paid and
(3) the prepayment is non-refundable
Yes, it looks ambiguous at first. But they're simply telling you that more than 30 days out there is no charge to cancel — some hotels charge cancelation fees — but you won't get your money back if you do.
The ambiguous bit is the implication that there is therefore an additional charge (not specified) if you cancel
within 30 days of the stay.
I wouldn't touch this hotel with a bargepole — find somewhere else. $249 a night is ridiculous to be surrounded by rowdy football fans for two nights.