When you're thinking about outfitting a home office, making that space suitable for audio and video calls is a multi-step process. You need to make sure that you hear the caller, that you are heard clearly, and that your environment is reasonably well-lit.
How do you sound?
You would prefer if people didn't hear everything in your environment, so investing in an expensive headset or microphone with noise-canceling features will help.
Making yourself sound less echo-ey is surprisingly easy: muffle the ambient noise slightly. For most spaces this involves both carpeting the floor or putting an area rug in place, or using a sound baffle to speak into so that the noise doesn't bounce as much.
You may also experiment with using different input than your laptop microphone, which tends to pick up things like typing and doesn't have much of a filter. Consider using a USB microphone or another plug-in source that is hidden from the screen when you're talking. You may not need a boom mic, but either a headset or a simple plug-in microphone will help. Test this set up by recording a standard script and then playing it back so that you can hear how scratchy (or blissfully quiet) things sound in your environment.
Note: changing how you sound is different than noise-canceling headphones, which do a great job of smoothing out the noise you hear from other people and do not change the sound those people hear at all.
How well do I hear them?
This is the easiest part of the problem - making sure you are able to hear your caller well. A basic headset will help - if you use an Apple device, the stock headphones work surprisingly well, or a headsets from Logitech are a good bet. You don't need super fancy, just comfortable.
If you use a headset intended for headphone and microphone jacks and you only have USB or a USB Hub, buy a USB sound adapter.
Does the environment look ok?
When you are on a video call, you'll need the background to be simple and avoid distraction. A complicated solution might be a video backdrop and a stand; while a simple solution might be a neutral colored bedsheet that you hang on your wall so that you avoid displaying the contents of your alcove on a remote call.
Not every video call is made equal - for example, Zoom will have different results from GoToMeeting or Google Hangouts. You'll need to experiment to find the best combination.
Tune your network
This part might be obvious, and it's worth upgrading your network equipment so you get the most out of the internet connection you have. Apple and eero both have excellent routers that make sure you are not dropping packets.