Our car keys have an uncanny ability to get lost inside coat pockets or underneath couch cushions — or to disappear altogether. Before the 1990s, this disappearing act wasn't a big deal. You could get a replacement key at any hardware store or locksmith and, of course, the car dealership. But that ease of making a new replacement key also made it easy for a thief to steal your car. These days, advances in key fob technology have made vehicles more difficult to steal, but the price has been costlier car key replacements.

Here's a rundown of what you'll face in the way of cost if you have to replace your key, along with some alternatives that could lower the bill. The prices quoted here are for Santa Monica, California, but parts and labor costs in your region will vary.

Basic Keys and Fobs

On most modern cars, an electronic key fob — also known as a remote or transmitter — is an integral part of the key set. The cost of replacing a key fob remote can range from $50 to over $100 depending on the automaker and complexity of the design. All key fobs need to be programmed. Some dealerships will do it for free, while others will charge a half-hour to an hour of labor.

But there is a way around this fee. Most key fobs can be programmed with a specific combination of button presses on the remote and key turns in the ignition. Some owner's manuals will show you how to do it, and you can also find this information online.

Finally, you can purchase aftermarket key fob remotes online or from a locksmith. Like most aftermarket products, the quality will vary, but they are a less expensive alternative.

Transponder Keys

After the mid- to late 1990s, manufacturers began placing a transponder chip in the plastic head of the car key. The chip emits a signal to a receiver in the ignition. If this "immobilizer" detects the wrong signal — meaning that the wrong key is in the ignition — the vehicle will not start.

A transponder shank is either a basic car key or a laser-cut key (more on laser-cut keys later). The major difference between a basic car key and a transponder key is that the chip in the transponder key must be programmed before it can start the vehicle. All dealerships have the machines necessary to program the key. Some might program it for free, but others will charge up to an hour of labor. Most auto locksmiths should also have these machines.

In some vehicles, the transponder key and the fob are an all-in-one unit, which adds to the price of the car key replacement and limits the places you can find a replacement.

We checked the price of a basic transponder key on an older Ford F-150. The dealer quoted us $160 for the new key and an additional $75 for the fob. If you go to a locksmith, expect to pay about $20 to $30 less.

A potential low-cost alternative for access to your car is to order a basic car key without the transmitter. This key will do everything but start the engine and can come in handy if you ever leave your keys inside the vehicle.

If you're the type who frequently loses car keys or locks them inside the car, you might be able to save money on the programming by creating a third car key to have as a spare. If you already have two car keys, a number of vehicle brands will allow you to program a third key on your own. You can have a locksmith cut this new key and then you follow the procedure for programming, which can frequently be found in your owner's manual. If the manual doesn't show you how, try searching online for the procedure. Try "How to program a (insert your year, make, model) key" as your search terms.

Our searches found a method that is said to work on many domestic vehicles. Insert one of your two working keys and turn the ignition to the "on" position for at least 3 seconds (the car does not need to be started), then repeat the process with the second key.

Now insert the new third key and again turn it to the "on" position for another few seconds. This step should program the extra key. But before you try this method and spend money on a key, we suggest you check with the dealership or your local automotive locksmith to see if the process is one that will reliably work with your car.

Laser-Cut Keys

You can tell a laser-cut key apart from a basic car key because the shank is slightly thicker and has fewer carved-out grooves. Laser-cut keys are often referred to as sidewinder keys due to the distinctive winding cut on the shank. The machines needed to cut these keys are significantly more expensive than standard key-cutting machines and are not as likely to be found at every locksmith or hardware store.

Laser-cut keys also have built-in transponder chips, and they need to be programmed at the dealership or by a locksmith, preferably one who is a member of the Associated Locksmiths of America (ALOA). You can search for a certified locksmith near you by visiting the ALOA website.

All-in-one laser-cut keys are becoming more popular, but as we mentioned, these keys are more expensive and typically need to be replaced at the dealer. Including labor, they can range from $150 to $250.

Switchblade Keys

Switchblade keys have shanks that fold into the key fob when they're not in use and pop out with the press of a button. They can have a basic cut or a laser cut. One small advantage of the switchblade key fob is that its components can be purchased separately. If for some reason your key is damaged and no longer works, you can buy the shank separately for about $60-$80. But the more likely scenario is that you've lost your key, in which case you'll need both it and the fob into which it folds, which can cost between $200 and $300 once you factor in the programming of both components.

Keyless Entry Remote

A keyless entry remote, also known as a "smart key," isn't a car key in the traditional sense. It is a key fob that is either inserted in the dash or, in newer vehicles, stays in your pocket or purse. The driver can then enter the vehicle and start the engine with the press of a button.

A keyless entry remote's main form of security is its ability to use rolling security codes. The system randomizes the correct code and prevents thieves from hacking it through the use of a device called a code grabber. The vehicle's computer recognizes the code emitted by the smart key and verifies it before starting the engine. Mercedes-Benz was one of the first automakers to use this technology and even coined the term "smart key." Every vehicle in its lineup now uses a form of smart key. That said, this technology is not theft-proof, and there have been a number of cases where high-tech thieves have been able to gain entry into a vehicle with a smart key.

Nearly every car brand now has a smart key bundled in its higher trims or technology packages. Keyless entry remotes are available in anything from a Nissan Altima to a Ford Escape.

These keyless entry remotes limit your options for a new key. The replacement remote must be purchased at the dealer or a factory parts reseller. And while it's handy to carry smart keys in your purse or pocket, these are the very places you will feel the pain when you lose them. The cost of replacing and reprogramming a smart key can range from $220 to over $500 for some luxury vehicles.

Better Safe Than Sorry

There's no denying that modern keys are expensive. And so the best defense against losing them is a good offense. It is better to get a spare key now, on your terms, than to stress out and spend the money in what might be an emergency. You can take advantage of the cost-cutting methods here and avoid the labor charges by programming the key yourself.

Finally, if you are someone who's tempting fate by only having one set of keys, consider this: If you lose all the keys to your car, you will need to get it towed to a dealership, and it can potentially cost you close to $1,000 to replace the locks on your car.