If you’re making travel plans that involve hotels, there are some tricks you’ll want to know for finding the best offers.

A number of big hotel chains are running promotions you can take advantage of only if you register, at no cost, before booking a room.

And with hotel and travel sites all promising that they offer the lowest prices available, you need to know about the guarantees behind those offers, which can result in even better deals or a free hotel night.

Promotional deals aren’t always listed on a hotel chain’s website where you would book a room. Instead, they often are listed on the hotel company’s rewards program site. Always check before you book.

Here are some of the deals going on now:

With Marriott, which includes 17 hotel brands such as Fairfield Inn & Suites and The Ritz-Carlton, those who register by July 31 for “The Unexpected Bonus” on the Marriott Rewards site can earn a free night for every two stays at any participating hotel through Sept. 2. A “stay” is each time you check in and out. If you’re not a Marriott Rewards member, you’ll need to sign up, which is easy and free.

I took advantage of a similar promotion a year ago on a trip to ski in Colorado. I stayed in a hotel near the airport the night I arrived in Denver and again on the night before I left — that’s two stays — and got a free night to use later.

The free night is good at any Marriott in the chain’s Category 1-5 properties. The Fairfield Inn at Greenville-Spartanburg airport is an example of a Category 1 hotel, while the Charleston Marriott is a Category 5. A free night could be worth what you paid for two nights elsewhere.

Best Western is offering a similar but less generous promotion. Register for the deal and stay three separate times at a Best Western by June 9 and you’ll get a $50 Best Western gift card. It’s $50 that you won’t get without registering for the deal.

Hilton, whose brands include Doubletree and Hampton Inn hotels, is offering a bonus points deal. Register for the “Daily Grand” promotion and you’ll get either 1,000 or 2,000 bonus Hilton Honors points every night you stay through June 30 (1,000 for weeknights; 2,000 for weekend nights).

Hilton Honors points can be accumulated and used for rewards such as free hotel nights. The bonus points are in addition to points earned normally with each stay.

Starwood Hotels, whose brands include Sheraton, Westin, Aloft, and Four Points, also is offering a bonus points deal. Register and earn double Starpoints for stays through July 31.

Starwood also is offering a new cross-promotion with Delta allowing some SPG rewards members to earn both Starpoints and Delta Air Lines miles on Delta flights. You have to register for the Crossover Rewards promotion separately.

In each case, you’ll need to be a member of the hotel’s rewards program.

Wyndham Hotel Group is offering bonus points that you don’t have to register for, but, of course, you can get and use their points only if you’re in their rewards program.

Typically, reward program members accumulate points for staying at hotels and for other activities, and those points can be used for everything from gift cards to free travel. Once you’ve signed up for a rewards program, you’ll get emails alerting you to future promotions requiring registration.

When it comes to getting the best rate, it seems like everyone claims they have the lowest price. That’s not always true, and that’s where best-price guarantees are important.

Generally, in order to take advantage of a best-price guarantee, you’ll have to book online, then prove that you found a lower price on exactly the same thing — room type, dates, rate plan — on a different website within a short period of time, such as 24 or 48 hours. Find a better price, even if it’s just a dollar or two, and you can get a free room night in some cases.

For example, InterContinental Hotel Group (Holiday Inn, Crowne Plaza, Candlewood Suites, and other brands) says that if you find a lower price “for the same hotel, type of accommodations and rate restrictions on the same date(s), we’ll not only match that lower room price, we’ll give you your first night’s room price free.”

Choice Hotels (Comfort Inn, Sleep Inn, EconoLodge, other brands) offers a similar guarantee.

Hyatt will match a lower price and give you a 20 percent discount for your stay, which could be worth more or less than a free night depending on the length of stay.

Travel websites also have guarantees.

If you book through Expedia and find a better price within 24 hours, they’ll match it and give you a $50 coupon. Travelocity offers a similar guarantee. Now, $50 off future travel isn’t as good as a free night on the trip you’re booking, but it puts some money behind the promise.

Hotels.com will refund only the difference in cost if you find a better price.

Just about every hotel chain and travel site has a price guarantee, and these are just some examples. I know it’s worth checking because I have received a free room night using one of these guarantees.

Reach David Slade at 937-5552 or Twitter @DSlade News.