I once lost my keys and didn’t realize it until I was standing at my front door, digging through my purse in the middle of the night.

When I didn’t hear the jingle jingle, I panicked. My dog was locked on one side of the door and I was locked on the other. I had been gone for hours. She was probably anxious, maybe tearing up my stuff, and definitely needed to go out.

As visions of chewed laptop power cords and flying couch stuffing danced in my head, I frantically searched for a locksmith on my phone. I called the first one I found, he showed up in a beaten-up Toyota Camry, and $110 later I was inside my apartment.

I did a few things wrong that night and spent way too much money. Here’s how you can avoid it.

1. Keep a spare

The best locksmith is one you never need to call. Start by making a spare set of your keys and giving them to a nearby neighbor, friend or relative you trust with access to your house or car.

For house keys, retailers like Walmart now have a DIY key-making machine. You pay a nominal fee (less than $5 in my area) and the key pops out in about five minutes. You can also have keys made at home improvement stores, dry cleaners, and even at concession stands in the airport.

Most car keys have a computer chip inside matched to your car, so you can’t make copies in a key machine. You could have a dealership make your keys, but home improvement stores like The Home Depot will also make them. I paid $86 (a $64 savings over my local car dealership).

2. Get referrals

Next, identify a reliable, affordable locksmith before you need one. Ask friends and family for referrals. Create a list of locksmiths to check out.

You can also look online for a locksmith. You’ll still need to take a closer look yourself, but it can get you started:

• FindALocksmith.com

• Locksmith.com

• Find My Locksmith

3. Do your research

The Federal Trade Commission warns that not all locksmiths claiming to be local actually are. In fact, some larger companies may have 30 or more listings in your local phone book all claiming to be based in your town. When you call the number, you’re sent to a call center, which in turn sends out an untrained person to do the job. And since they’re not local, you’ll pay more mileage for the trip. Here’s how to avoid that:

• Research the address. If an address is listed, look it up on Google Maps to make sure it matches a local locksmith shop, not an empty lot or unidentified building.

• Research the phone number. If no address is listed, use a site like White Pages to do a reverse phone number search for the address. Then plug the address into Google Maps.

• Check for reviews. Review sites like Yelp can help you decide if a locksmith is legitimate and good.