You can shop for pretty much anything online these days, but if you're shopping for a puppy, you could be barking up the wrong tree.

Scams involving pets aren’t new, but the scam-warning site, operated by the National Consumers League, warns that it has been seeing a surge in pet scams in 2015.

Scams targeting people seeking pets vary, but the hook is the same: The crooks get you to feel connected to a particular animal and then keep asking for money. Similar scams target people looking for missing animals in an attempt to extract payment from pet owners desperate to be reunited with four-legged companions.

The key to avoiding such scams is being able to recognize them.

Related: 2 Vaccines Your Dog Absolutely Needs, and 4 He Might

"These scammers are criminals. Their goal is to take your money," warns the International Pet and Animal Transportation Association (IPATA), which publishes a list of known pet scam email addresses and websites. "They will lie, they will tell you sob stories, they will send you pictures of adorable animals, they will assure you of their faith and religion — anything to get your money!"

Here are some scenarios to watch out for

Free to a good home. It starts out quite innocently: You see an ad that says some pet is available for free to someone who will give it a loving home. Perhaps they're moving, being deployed or just no longer able to care for the animal. If you respond and hear back that the person who is giving away the animal is out of town, you're likely looking at a scam, according to the IPATA. Why? For one thing, the “out of town” excuse serves to explain why you can't see the animal in person. For another, it creates the opportunity to ask for money to ship the pet to you.

Suddenly, that "free" pet costs you, and the money for shipping you’re asked to provide might be just the beginning. Any number of other additional charges could crop up (for a crate, shots, additional shipping) if you pay the initial fee. One victim, whose story is used as a warning from the ASPCA, paid $150 after the first request. She says she was asked by the supposed shipping company for another $420 because the shipping crate was inadequate. That's when she realized she was being taken, she says.

Related: Is It Safe to Buy Pet Medication Online?

Cheap prices for specific breeds. The most recent warning about this type of scam came from the Better Business Bureau. It flagged a website purporting to sell bulldog puppies for $499. That might seem like a lot to pay for a dog, but it's a fraction of what the type of dogs advertised typically cost, the BBB says. The offer included free nationwide shipping, but one victim told the BBB she was then asked to pay more than $1,000 for shots and a shipping crate. A BBB investigation found the website used a bogus address, photos of dogs lifted from other websites and testimonials copied from other sites.

Found pet. In this scam, the crooks find you. If you've placed an ad seeking help finding a lost pet, you're a potential target. You'll get a call from someone who says he’s found your pet. Chances are the scammer will have been “just passing through town.” He may or not tell you your pet’s been injured. In one scenario reported by the ASPCA, the caller told the victim he had just moved and found her lost cat in his moving truck. The victim says she was then asked to send $300 to cover the cost of getting the animal home. Another variation involves telling the pet owner the animal had been hurt and asking for the cost of veterinary bills before the animal can be returned.

Related: The Downsides of Homemade Dog Food

Avoid getting scammed

The Better Business Bureau, National Consumers League, International Pet and Animal Transportation Association and ASPCA offer these tips to avoid falling victim to pet scams:

  • Don't buy a pet online. If you can't see the facility or animal in person before purchasing it, it's questionable the animal even exists.
  • Beware of low prices. Find out how much the breed you're interested in really costs and beware offers that are well below that.
  • Beware certain payment requests. If the only way to pay is by putting money on someone's debit card through such services as MoneyGram or Western Union, hoist the red flags. Those services are the primary means of conveying money in scams because they are cash transactions, difficult to trace and nearly impossible to reverse.
  • Look for a pet locally, particularly through local animal shelters. Costs will likely be lower than through a private seller. 

Mitch Lipka is a consumer columnist and product safety expert. He was the 2011 recipient of the "Kids Best Friend Award" from Kids In Danger for his commitment to reporting on children’s product safety.