Who doesn't love Craigslist?! The site has made — or saved — savvy shoppers countless dollars. But for all the good this online trading post provides, there are some Craigslist no-nos. Big ones.

Here are the dangers and downsides of some Craigslist finds for your home — and the reasons why you'll want to stay far, far away.

1. Computers or smart home equipment

Jason Glassberg, co-founder of the ethical hacking and cybersecurity firm Casaba Security, advises against buying preowned computing devices (laptops and tablets) or any smart home devices (e.g., thermostats) that can connect to the web.

The reason: "The consumer has no idea how the device was previously used," says Glassberg.

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In most instances, the seller is likely just looking to make a quick buck. "But there is a chance the seller placed a remote access tool on the device or deliberately installed implants and backdoors," says Glassberg. "This could allow the seller to remotely access the device, steal information, copy passwords, screenshot your desktop, enable the microphone or camera — you name it."

And even if there is no nefarious intent, a used device may be past its warranty or support period. This means a new owner won't be able to update the software with important security improvements and performance fixes.

2. Used appliances

Chances are the appliances weren't disconnected properly, making them harder to reconnect later.

"And their effectiveness is very hard to evaluate if you can't see them run," says Miranda Benson of Dolly, an on-demand moving and delivery app that handles Craigslist pickups. So unless the seller lets you do a test run, steer clear.

3. Mattresses, futons, or anything that's slept on

Two items you can snag a great Craigslist deal on? Bed frames and headboards (I've bought both on the site). But a mattress is a very different story.

"A mattress could contain bed bugs, other pests, or even bodily fluid, all undetected at first glance," says Sophie Kaemmerle, a home and neighborhood safety expert at Neighborwho.com. Yuck.

The Federal Trade Commission lists what's required in the sale of a used mattress. For instance, in some states the mattress must be disinfected and the fabric replaced. Other states allow for the sale of only the springs from a used mattress. (Because who wants to sleep on the residue of the previous owners?) Unfortunately, these requirements are not mandatory on Craigslist, making buying a used mattress a straight-up health hazard.

4. 'Designer' goods

There’s a ton of counterfeit knockoffs for sale on Craigslist. Need an example? An Hermes Birkin bag that retails for almost $19,000 is currently on Craigslist for, um, 70 bucks. Same goes for any home decor items, from "Tiffany" lamps to "Eames" chairs. Since it can be difficult to authenticate designer items, ask for any documentation or receipts to verify they're the real deal.

5. Anything safety-oriented for children

See great kid's toys or clothes on Craigslist? Go for it. But buying second-hand car seats and cribs on Craigslist is a huge risk, says Trae Bodge, a smart shopping expert and TV commentator.

With car seats, even if they look brand-new outside, the internal structure could be compromised by a prior accident and therefore be less safe. Car seats also deteriorate over time, and the padding loses its ability to protect a child.

In addition, certain car seats and cribs may have been recalled due to safety issues but still show up for sale on Craigslist, says Kaemmerle. When it comes to the safety of your kids, sometimes it's best to buy new.

"What could possibly go wrong?!" (iStock)

6. Furry friends

When I found a kitten on the street, I posted a "Lost Cat" listing on Craigslist. I didn't find the cat's owner, but I did get a flurry of emails from cat-flippers. These are people who claim lost pets in order to resell them on Craigslist.

Other unsavory characters, like those who run puppy mills, use marketplaces like Craigslist to traffic all kinds of animals, sometimes as part of larger criminal enterprises, says Natasha Mehra, product development manager of 5milesapp.com, an online community of buyers and sellers of secondhand goods and local services.

A better idea is to find a pet through a vetted organization such as a nonprofit or a no-kill animal rescue organization like the ASPCA.

This post, "6 Home Items to Never, Ever Get on Craigslist," appeared first on Realtor.com®.