If last-minute hotel booking apps make you think of impetuous travelers on a budget, think again. The market for such apps and websites is becoming increasingly crowded, making it easier for those looking for upscale hotels to find eleventh-hour discounts. During recent searches I found a room at the Four Seasons Hotel Miami for about $157 (compared with $259 on the hotel’s website), a room at the Westin Resort & Spa, Cancún, for $75 (as opposed to about $200) and a room at the White Barn Inn & Spa in Kennebunkport, Maine, for $300, down from $630.

Which sites will check you into the lap of luxury? I spent days with new apps and old standbys to determine the best tactics for nabbing a high-end hotel room at a (somewhat) down-to-earth price.

Let’s begin with some guidelines.

Look out for taxes and fees

Many apps and sites do not display the entire nightly rate on their homepages.

For instance, to see the total cost of a room on the popular last-minute booking app Hotel Tonight, you must tap the name of your desired hotel (shown with the price of the room) and then, on a different screen, tap a “book now” bar to see that price with taxes and fees. On a recent Tuesday night, a room at the Viceroy Santa Monica Hotel in California was listed as $440 on the Los Angeles hotel search page, yet with taxes and fees it was $528.

Check the dates and the fine print

The current day is not necessarily the default setting on the apps and sites. This is the case with a new app called Stayful, which allows users to bid for boutique hotel rooms at the last minute or up to 30 days in advance.

Also, check the length of stay. The app LMT Deals from Last Minute Travel has a default stay length of two nights; you must change it if you want more or only one.

And always read the fine print. Your deal might be nonrefundable, or room type might be assigned to you by the hotel.

Shop around

Just because a site or app puts inventory online at a particular hour doesn’t necessarily mean that’s when you should pounce. There may be more appealing deals later on that app, or on a different app or site.

Time is money, so decide how long you want to comparison shop. Take a search I began on a Tuesday afternoon. It was for a room at the Gramercy Park Hotel in New York, where guests have access to a coveted key to the area’s private park, locked since the 1840s. At 1:42 p.m. I opened Hotel Tonight. There were two deals for rooms that night at the Gramercy. The cheaper one was $549 with taxes and fees. That was $73.01 less than the lowest-priced room on the hotel’s website.

Next, I searched for the Gramercy Park Hotel on Priceline.com and found a room for $576.10 with taxes. The Hotel Tonight rate was cheaper than Priceline by more than $27. Would the Tonight rate continue to hold up?

Nope. On Hotels.com I found a room at the Gramercy for $541.08, taxes included — almost $8 less than the price on Hotel Tonight. A new winner had emerged.

Later that afternoon, I decided to see if I could do a bit better on Expedia. I did. At 3:30 p.m., Expedia.com was offering a room at the Gramercy for $540.31 — 77 cents less than the rate on Hotels.com. (You could make 77 wishes in a fountain with those savings.) Overall, that rate is nearly $82 less than the lowest price on the hotel’s website ($622.01). As it turned out, Travelocity had the same deal ($540.31), so both sites beat the competition.

Is saving $82 significant when you’re talking about a $500 room? Yes. And there’s a larger point: Shopping around can whittle down the cost of any class of hotel room.

Bid and gamble

If you like to gamble, the new app and website Stayful will allow you to bid on a room. It recommends what that bid should be, though you can go lower, insultingly lower. A “bid success indicator” — a color-coded bar not unlike the Homeland Security Advisory System chart — ranges from green (meaning you are likely to have your bid accepted) to red (fat chance).

On a Monday night at 8, I decided to bid the least amount possible for a room at the Standard, High Line, the luxury boutique hotel that straddles the elevated park in the meatpacking district in New York. The indicator on the app was still in the green when I lowered the “recommended bid” — $716 for a room that would normally be $795 — to $610 using a sliding tab. When I further decreased my bid, to $384, I was in the orange danger zone. By $267 the indicator was the color of Rudolph’s nose but, hey, I know rooms there can be had for less than $250. I slid the tab to the lowest possible number, $47 (for which there is no color) and clicked the “submit bid” button. “Yikes!” said a pop-up message, “$47 per night has a slim chance of being accepted by the Standard High Line.” I could tap a big green bar that said “Change bid” or a teeny-tiny underlined sentence that said, “Continue with my original bid.” I pressed the tip of my finger to the little text. “Please wait while we are negotiating with the hotel,” said the app.

It was, alas, a swift negotiation. “Sorry,” a message said, “your bid was declined.”

I can’t say I was surprised. Perhaps the best way to incorporate this app is to research everywhere else first, then bid lower than the best price you’ve found.

Check the Big Three

By their nature, last-minute sites deliver uneven results, particularly when there’s a convention in town and rooms are at a premium. In general, though, what’s available in the morning may disappear by lunch, while new options from brands such as Viceroy and InterContinental can appear at any moment. And don’t expect one site or app to be consistently superior. Sometimes they’re equal.

On a recent Tuesday night I found the same price for a room at the Ritz-Carlton New York, Central Park ($745 before tax) on Hotels.com, Expedia.com, Priceline.com, the Ritz Carlton website and the app Booking.com Tonight.

So what’s a formula for last-minute success?

Balance cost savings with research time by comparing just three tools:

• Hotel Tonight or Booking.com Tonight (because these apps are intuitive and have some high-end hotels).

• Your favorite third-party site (such as Expedia) or Kayak.com (to check prices across multiple sites)

• The hotel’s own website.

If you have an extra minute, try using Stayful to bid lower than the best price you find. Also, remember there’s another technology that allows you to discover if a hotel will grant you a last-minute deal. It’s called the telephone.