But there was a hitch. After he talked about it with his wife and was ready to book, the rate had increased by $40 a night when he logged on again the next day.

“I assumed if the sale was on for 72 hours, the rate would be good for 72 hours,” said Mr. Buszkiewicz, fiscal officer for the Indiana University School of Education.

Making hotel reservations used to be straightforward. Guests booked a room and could generally cancel without penalty until the day of arrival.

Now, as hotel chains consolidate, last-minute booking apps proliferate, and short-term rental sites like Airbnb and HomeAway grow, experts say the reservations landscape is undergoing an upheaval with new and higher fees and new restrictions on reservations that are driving new sources of revenue.