Las Vegas has an enormous amount of rooms. Including the NYNY, the 4 hotels that are immediately at that intersection have over 12,000 rooms between them (well, down to 11k these days as the Tropicana has closed), and that's just a small portion of what's on The Strip as a whole. Prices vary wildly depending on what's going on. They are high on the weekends (sometimes much higher), and usually low during the week unless there's a big convention or other event in town. The fluctuation in room rates is more dramatic than I've seen in any other city.