It is normally listed on the hotel webpage (fact sheet) and can vary drasticly. Some cost nothing, some are refundable deposits and some I have seen as high as $250 deposit/NR. Don't even get me started on how a hotel can say it is "pet friendly" with a $250 NR deposit.

JW Denver is $0. A Fairfield Inn in St. George UT is $30 NR. The Cosmo on the strip in Vegas is a $50 refundable deposit.

It just depends.