Use the code and mail in the form to get your rebate.
Brad's Deals Editor Jim,
Get up to $100 back as a rebate when you use the promo code REBATES18 during checkout at Hotels.com. The offer gets you $20 with a three-night booking, $30 with a five-night booking, $50 for eight nights, $75 for 10 nights, or $100 for 12 or more nights. Because this is a mail-in rebate, you'll have to fill out and mail in a certificate (found on this page). It gets credited back to the credit card you used during booking. Book by 12/31. Travel by 3/31/19.