No man is an island, but it sure is nice to have one all to yourself every now and again.

While the cost to rent the exclusive hideaways can cost up to  $20,000 a night,  savvy travelers can score an entire isle for less than $500 a night — if they know where to look.

The sea off the coast of Nicaragua. (riderfoot / iStock)

Go South. If you’re looking for tropical private island rentals on the cheap, head to Central America, to places like Belize and Nicaragua, says Eric Grayson, a the founder of travel firm Discover 7 Travel. These destinations often offer a Caribbean-esque experience (azure water, sugar-sand beaches) but at half or less of the cost.

Some of the most compelling options: Bird Island, Belize, which costs about $395 a night and is ringed by a fish-filled coral reef and boasts a hip, three-bedroom turquoise bungalow; and Tahiti Island, Nicaragua, with its four-bedroom pad complete with pool for about $200 a night. If you want a full-service island (think personal chef and other staff), try the 2.5 acre Pink Pearl Island in Nicaragua, which comes to around $425 a night if you stay a week; the island can accommodate 10 people.

Indonesia also offers a private island deals, says Grayso, as does South America, says Misha Gillingham, a luxury travel expert.

Look in your own backyard. You don’t even have to get on a plane. Some of the best deals are in the U.S. and Canada, says Chris Krolow, the chief executive of private island marketplace Private Islands Inc.  Try this 11.5-acre private island on Lake Dowd, roughly 30 minutes from Minneapolis, which costs just $265 a night; the home on the island sleeps eight. Or the 10-acre Eagle Island ($480 a night for up to 2 guests, $550 a night for up to 12 guests), near Darien, Georgia, where you can watch the sunset from your 1,500-square foot wrap-around porch. There’s also Deepwater Island (less than $300 a night), roughly two hours from Toronto, which is nestled in a  protected bay on a bespeckled granite island.

Size and water type matter. Smaller islands are often cheaper than larger ones, simply because their size limits the types of amenities that can be built on them, says Grayson. Travelers are also more likely to find deals on islands on lakes and rivers, says Molly Fish, a travel expert with home rental site HomeAway — as these tend to be less desirable than those on the ocean.

A small island may yield better deals. (stevenallan / iStock)

Don’t pay sticker price. Even a private island that advertises a price tag that’s well above $500 a night can be had for less. “With most of them there is room for negotiation,” says Grayson. Start by looking at rates in the off season, which are often 25% off or more from high-season rates. (Insider tip: Book a room at a small hotel in the off season, and you may find yourself the only one on the island anyway, says Gillingham). From there, negotiate the nightly price down.

After that, tackle the extras: Even modest private islands may require cleaning fees or pet deposits, says Fish, who recommends you ask for an itemized list of rental expenses before booking your stay and negotiate them.  Grayson notes that it can be cheaper to bring services — like a personal chef — in yourself. For example, in Central America, a private chef might only run you $50 a night.

A full-service island — where a chef, cleaning person and others are on staff — isn’t always more expensive, when you consider that you likely have to buy all your own groceries, pay a cleaning fee, fund your own transportation to and from the island, and more on a self-service island. Don’t neglect to factor in the fact that cheap islands may lack amenities you consider basic, like toilets that flush.

Get the group rates. Obviously, going with a group can slash your costs per night on the island. But here’s another benefit: With that many people, you may also be able to get a discount on airfare too, says Grayson.