There are several websites that help you in renting out your own property such as Zillow, Plaza Estates property sites and so on where you can list your home easily.
The cost for a basic level listing isn't too expensive, and with one or two rentals even a top-tier listing will pay for itself fairly quickly. They also allow you to offer specials, such as last-minute booking discounts to fill gaps in your calendar. You may want to consider Craigslist's Vacation Rental section as well. http://www.plazaestates.co.uk/properties-to-rent/buying-to-let