You could be eligible for a $75 statement credit on any purchase of $300 (or more) made with an American Express card through HotelStorm.com, a discount hotel-booking site.Here’s how it works:Log in to your American Express account and register for the offer. Note: It’s a targeted offer, so you might not see it. If you don’t, tweet using an account linked to your Amex and use #AmexHotelStorm. Wait for confirmation from @AmexOffers that the offer has been added to your account.Log on to HotelStorm.com/Amex.Book between now and March 12, 2017.That’s it. If you’re not familiar with HotelStorm (we weren’t either), it looks to be a general third-party hotel-booking site. Just punch in your location and get a list of available hotels in your area.Based on a quick search, HotelStorm’s rates appear to match those available through other travel agencies, as well as Marriott’s site. For example, using the same dates, all three sites showed identical availability and prices.Here’s the booking through HotelStorm:Booking La Concha in San Juan, Puerto Rico on HotelStorm.com.Here’s Trivago:Results for San Juan, Puerto Rico on Trivago.com.And here’s directly through Marriott:Booking La Concha in San Juan, Puerto Rico on LaConchaResort.com.Just be aware: Typically, you won’t earn points when booking through a third-party site. So if you’re looking to boost your account balance, it’s still best to book via a hotel’s website — and use a credit card that will earn you bonus points for your purchase.Have you ever used HotelStorm.com?Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.[card card-name=‘The Platinum Card® from American Express’ card-id=‘22504813’ type=‘javascript’ bullet-id=‘1’]