When building out an entry-level home theater system, one of the first things you need to decide is what kind of sound system you actually want. There are three main options to choose from: a soundbar system, an AV receiver and bookshelf speaker system, and home theater starter kit. There are advantages and disadvantages to each (which we've highlighted below), but once you've figured out the sound system you can pretty much pair it with any TV and streaming device with it.
Option 1: The Soundbar System
The easiest option is to build your home theater system around a soundbar. This is because it plugs directly into your TV meaning you don't need an AV receiver. A lot of soundbar manufacturers, like Sonos, Bose and JBL, also build compatible subwoofers and rear-channel speakers that you can purchase as a home theater package or separately (if you decide you want to build out your system at a later date. The downside is that you don't get the flexibility to build out and customize your system in quite the same way. (You can't pair a Sonos soundbar with a Bose subwoofer or Klipsch's rear-channel speakers, for example. ) But if you just want to be done with the project, this is a great way to go.
Option 2: AV Receiver and Bookshelf Speakers
The most traditional route to building a home theater is to buy an AV receiver and a pair of bookshelf speakers. There are a couple advantages to doing it this way. There's more room for customization as each component isn't tied to a larger ecosystem. It gives you the flexibility to add better speakers, a subwoofer or even surround speakers later down the road (provided your AV receiver supports a larger system). Also, if you have a pair of bookshelf speakers that you love, you can easily turn them into a pair of home theater systems. The downside of this is that it's a little complicated. If you're looking to save money and you don't plan on upgrading your system later on, you can buy a more affordable AV receiver that doesn't support Atmos and doesn't support surrounds.
Option 3: A Home-Theater-In-A-Box System
The third option is to buy a home-theater-in-a-box system, as it's essentially a smaller and more affordable surround sound system. Most come with an AV receiver, but not all so you'll have to look out for that; if you need to purchase one separately, it'll likely add $300-or-so. In general, however, this is the perfect compromise between a high-quality soundbar and a full-fledged surround-sound system.