Most of today's TVs don't have great sound quality. In fact, many TV manufacturers even recommend buying a sound bar or surround sound system because of it. The good news is that you can buy a decent soundbar for pretty cheap. There's also no need to deal with an extra component, like an AV receiver, because most of today's soundbars can plug directly into your TV.
The catch is that most affordable soundbars won't support high-end immersive sound technologies, such as Dolby Atmos — you'll probably have to spend at least $400 (but probably more) for a Dolby Atmos soundbar. But if you just want to get better sound out of your TV, 4K or not, you really don't have to spend much more than $150.
TCL Alto 6+
The Alto 6+ is an entry-level soundbar and wireless subwoofer that's designed to work seamlessly with any of TCL's popular 4K TVs that run Roku's smart operating system. It connects to your TV via an HDMI ARC connection. It does have built-in Bluetooth, so you can use it to play music from your smartphone when you're not watching TV. (If you don't care for the wireless subwoofer and you want to save a little bit of money, you buy the Alto 6 soundbar by itself.)
Sony's entry-level option is another decent soundbar that sounds considerably better than its $100 price tag. It's a 2.0 system — so no wireless subwoofer —and is perfectly sized to fit under a 50-inch TV. It connects to your TV via a simple HDMI ARC connection, and it supports Bluetooth for music streaming as well.
The Streambar is a tiny 2.0-channel soundbar that supports Dolby Audio. The really neat thing about it is that it actually has a 4K HDR streaming player — equivalent to the Roku's $50 Streaming Stick+ — that's built right into it. This means that it can turn any older "dumb" TV into a "smart" TV that's able to stream apps like Netflix, HBO Max and Peacock. Additionally, the Streambar is compatible with Alexa and Google Assistant, and it supports AirPlay 2.
Vizio V Series V21-H8
This is the most affordable soundbars that Vizio makes and, as its name gives away, is designed to be paired with the company's V-Series line of 4K TVs. ("V" stands for "value," in case you were wondering.) It's a 2.1-channel system that comes with complete with a wireless subwoofer. It's simple to install, connecting to your TV via HDMI ARC, and it supports Bluetooth streaming.
Polk Audio Signa S2
Polk Audio's Signa S2 is one of the best soundbar-and-subwoofer combos you can buy for under $200. It's a little over two years old, released in 2018, and that's one of the big reasons you can often find the Signa S2 steeply discounted. It connects to your TV via HDMI ARC and supports Bluetooth streaming. If you're looking for a loud home theater system with solid bass, this is as good as it gets in this price range.