Resorts and water sports marry throughout the Keys, giving couples and families, novices and veterans, chances to snorkel and dive. Some properties charge a required $15 (or more) daily resort fee for equipment rental, which can cover spa use and other services. A few rooms cost as little as $65 a night, but most range from $100 to $300. Some guesthouses and inns do not welcome children under 16, and some do not permit smoking.