If you google for something like "Budget podcast microphones", "low cost podcast microphones", the same mics keep coming up.
e.g
https://www.thepodcasthost.com/equipment/the-best-podcasting-microphones-on-the-market/#atr2100
and
https://www.omnicoreagency.com/best-podcasting-microphones/
and
http://www.makeuseof.com/tag/best-podcast-microphone/
They give a range of prices as well as brief reviews to help work out what you may or may not be getting for less or more money. Not all are USB
For recording, apart from the obvious of a quiet location the advice that gets given suggests a room with soft furniture and book cases to stop the sound bouncing around. Some people set up inside wardrobes or record with duvets over their head and mic to control sound bouncing around. If you have a desk up against a wall something pinned behind the computer such as a duvet will stop direct bounce back into the mic. Clothes horses with blankets or duvets to try and generate a recording booth will improve sound quality. You obviously don't need to do all these things, but they are worth experimenting with if you aren't happy with the sound you are getting. Most sound editing software will allow some post recording improvements.
You need to get close to the mic less than a foot, so you maximise the signal to ambient noise ratio which also means you may need a "pop filter", but getting close will help with cutting out ambient sounds.
I use a Rode video mic pro on a boom, or a rode smartlav+ but neither are USB mics and the latter is designed for a smartphone and needs an adaptor to plug into a computers mic socket.
I'm no expert on this, but I started making screencasts for teaching a few years ago and did a few online courses, reading etc and the key things were getting close to the mic, and treating the room to improve its sound characteristics, or do something that made you look silly like draping a duvet over your head. As Demilion suggested, the quality of the mic itself makee much less difference to the sound quality than doing these two things. I found a lot of advice by Googling for making podcasts or doing voiceovers "on a budget" about setting up a room for recording.
If I had a laptop with a microphone, I would probably be tempted to put the message you want to record on the screen, put a duvet over my head and laptop, and try speaking at different distances from the built in mic, just see it how it sounded, before buying a new mic. If nothing else it will give everyone watching a bit of a laugh.
Cheers,
Graham
