Most people assume a hotel has one price, and every site is just quoting it. It doesn't, and they aren't. The same room, on the same dates, for the same two guests, will show you different numbers depending on which site you happen to open β and the gap is often bigger than people expect.
Here's a real example. We ran a live price check on The Savoy in London for a 3-night stay in late September, two adults, no special deals or codes. Twenty-seven sites returned a bookable rate for the same room and dates. The spread:
That's an $842 gap between the cheapest total and what the major-name cluster charges β about $281 a night β for the identical room, identical dates, at the same hotel. Not a discount code, not a loyalty tier. Just which site you happened to book on.
A few real mechanics explain most of this, and none of them are a trick:
Different distribution channels. A hotel doesn't sell its rooms through one pipe. It sells directly, and it also sells blocks of inventory wholesale to consolidators, who then resell it through their own sites at whatever margin they choose. The big-name OTAs β Booking.com, Expedia, Agoda β mostly source the same "public rate" from the hotel's central reservation system, which is a large part of why they so often cluster within a few dollars of each other, as they did here. A smaller aggregator sourcing a separately-negotiated wholesale rate isn't bound by that same number, and can end up meaningfully cheaper (or, sometimes, more expensive).
Different commission structures. Every site that sells you a room is taking a cut, but the size of that cut varies by site and by the deal the site has with the hotel or wholesaler. A site with a smaller margin, or one running a promotion to win volume, can pass some of that difference on to you without doing anything shady β it's just a different business arrangement upstream of what you see.
Rate class differences that aren't obvious from the price alone. Not every "$X total" is the same product. Room-only versus breakfast-included, refundable versus non-refundable, and standard versus a wholesaler's specially-blocked allotment can all sit under what looks like a simple total price. In this audit several of the cheaper-to-mid-range results carried free cancellation up to a few days before check-in; some of the others didn't say either way. That's exactly the kind of thing worth reading before you assume two "identical" prices are actually the same booking.
Prices are not fixed β they float. Hotel pricing is closer to airline pricing than most people think: it moves with how much inventory is left, how far out you're booking, and demand signals the hotel's revenue system is picking up in real time. The numbers above are what 27 sites showed at the moment we checked. Run the same search tomorrow and several of them will have moved, in either direction.
The takeaway isn't "always book the cheapest number you see." It's narrower and more useful than that:
Check more than one site before you book, for the exact same dates and room. Not because any site is lying to you, but because they're genuinely not all quoting the same underlying rate.
Before comparing two prices, check what's actually included. Free cancellation is worth a real amount of money if your plans could change β cross-check it before assuming the cheapest total is the better deal. A non-refundable rate that's $50 less isn't automatically the win it looks like.
A big gap on well-known hotels is common, not suspicious. The Savoy is about as mainstream and heavily-distributed a hotel as exists in London, and it still had a $842 spread across sites people book on every day. Less prominent hotels, with fewer sites carrying their inventory and less pressure to stay in line with each other, can show gaps just as large or larger.
Because prices move, a price worth checking once is worth checking again. If you've already booked and cancellation terms allow it, there's no reason the number you locked in on day one has to be the number you pay on the day you check in.
That last point is the actual reason we built REIR β checking one hotel across two dozen sites by hand, then remembering to go back and check again after you've booked, isn't something anyone should have to do manually. REIR runs the comparison for you and keeps watching afterward, so if a lower rate for your dates shows up later, you hear about it instead of finding out by accident.
The Savoy audit above is one hotel, on one set of dates, at one moment in time. The mechanics behind it β channel differences, commission structure, rate class, and real-time price movement β apply to essentially every hotel booking. The gap won't always be $842. It's rarely zero.