So we’ve made this list of the best “20 under 20.” These twenty home security devices will help you secure, monitor, and smarten up your home. Unfortunately, security cameras can easily cost hundreds—if not thousands—of dollars. But, if you know where to look, you can find some amazing security cameras that won’t break the bank. For example, this security camera from ZOSI works in both outdoor and indoor locations and lets you choose between TVI, CVI, AHD, and 960H video output. It has LED lights and night vision, allowing you to see what’s going on no matter what time of day it is. Yes, motion sensors, like the ones that open the doors on the Starship Enterprise. Except, in this case, the motion sensors will detect movement at your home, apartment, office, or any other location. You can get an alert on your smartphone or other device when the sensor is triggered, and then check your cameras (or take other appropriate measures). You can get a great wireless motion sensor for less than $20, like this one from Kangaroo. There are many different kinds of motion sensor lights—from large, sturdy outdoor lights with built-in sensors to cheap indoor bulbs that can be inserted into your lamps and fixtures. If you want to spend less than $20 on motion sensor lights, we suggest looking at these options from Aukora and Boxlood. Many security companies, like Ring, sell mailbox sensors that are cheap and reliable. These devices alert you when your mailbox is opened. That way, you can know when your mail and packages are delivered (and you can know if someone else is “checking” your mail for you). “Who’s there?” “Nobel.” “Nobel who?” “No bell. That’s why I knocked!” Sorry for the terrible joke. But maybe you would have seen it coming if you’d had an awesome and affordable video doorbell installed. Smart doorbells can let you see everything that’s going on at your door, from package deliveries to door-to-door salespeople to neighborhood kids playing a prank. While the best video doorbells will usually cost you more than $50, you can pick up a perfectly good smart-ish doorbell, like this one from Honeywell, for well under $20. Smart smoke alarms have a bunch of features that the older devices you grew up with didn’t have. They can alert you when the alarm is triggered, even if you’re not at home. They can tell you when the batteries are low. You can link multiple alarms together for increased coverage and coordinated activation. You can grab a quality smoke alarm, like this one from Kiddie, for under $20. With a smart CO detector you don’t have to worry. If you’re willing to spend a little more than $20, you can get a quality carbon monoxide detector and smoke alarm combo device. Companies like Ring and SimpliSafe sell quality panic buttons for around $20 online. These devices are cheap, simple, and powerful. They work by adding an additional, physical barrier to opening your door. You can pick one up from a reputable company, like Defender Security, for well under $20. You can make a 911 call easily with a voice activated speaker. You can use your speaker to answer important medical questions. Elderly users can use smart speakers to alert loved ones in case of an emergency. The practical uses of these speakers is nearly endless. While the best smart speakers cost more than $20, you can easily find a decent, voice-activated speaker that’s less than $50. You can still get real results with a fake camera. The mere presence of a “camera” on the outside of your house, inside your business, or elsewhere on your property can do a lot to deter potential wrongdoers. You can pick up a set of fake security cameras, like these ones from BNT, for well under $20. You can also use smart plugs to program timed routines for lights, air conditioners, and other devices. If you’re going away on a long vacation, setting your lights to turn on at a certain time with smart plugs can help keep your home secure. Best of all: smart plugs are cheap. Here’s a breakdown of some of our favorites. These locks are easy to carry and install. You can pick one up from Addalock or another company for less than $20. With a door handle alarm, like this one from Sabre, you can use multiple settings: a pleasant chime to let you know when your family and guests arrive home, or a loud alarm that could wake you up if you’re sleeping and scare away anyone who’s trying to break in. While this system isn’t nearly as robust as one from Vivint or another full-fledged home security company, it can give you some peace of mind (and it’s a lot cheaper). These small GPS trackers can go on your car, in your purse, or with your other valuable property. If it gets misplaced (or stolen), you can easily track the GPS device using an app on your phone. Here’s a great example of a GPS tracker from Tracki. Security camera signs, decals, and stickers are very affordable and can be put up easily on your house, business, or rental property. Some of the best home security companies out there, like Simplisafe, offer packages beginning at less than $20 a month. These professional security systems can hook you up with powerful equipment, constant monitoring, and all kinds of useful services and apps to help you feel safe and secure in your home.