USB Mic for Voiceover Work

I have a co-worker that does a lot or PowerPoint shows and frequently has to do voice-over work on them.  I had to do some myself for one of her recent decks, and I simply write my script and go into the studio and record with my microphone into my preamp and have a nice clean sounding recording to put into the PowerPoint deck.  She is jealous of the sound clarity I got and is looking for suggestions on how to improve what she is getting in the most cost-effective way.
 
So, does anyone have any suggestions on a USB mic solution that is $100 or less that would sound significantly better than a average cheap USB mic?  I'm talking entry level prosumer stuff, and the biggest expectation is something that will have lower noise and a bit more clarity for spoken word.  Her current mic is pretty noisy and doesn't have great fidelity.
 
Thanks!

Thanks for that info, that is something to consider.
I asked her to let me know what she has now, but I think it's pretty cheap low-budget option, and not something very good.  I did a little looking and found a Blue Yeti USB that looks pretty decent for just over $100.  Seems to have pretty good ratings from what I've read and may do the trick. Has anyone used that mic?  The other advantage with all in one USB setup is that it might be simpler for her to setup and use.  I'm not located in the same state as she is and there wouldn't be anyone available to help her with setting up something with a mic into an interface.

The USB mike is the audio interface. So it's a simple matter of finding a USB mike that has the best sound quality. Finding that is a simple matter of knowing how to search the internet for good, trusted reviews. 
And some of them probably come with recording software too so watch for that. But Windows has a recorder built in. 
 
Another option is a Tascam or Zoom handy recorder. The sound quality for under $100 is top notch. 
She can also take it to record meetings and whatnot so serves double duty. 
 
 
Ha ha funny they even sell them at Wal Mart..  I paid $79 CAn for the one I bough for a friend . 
https://www.walmart.com/ip/Tascam-DR-05-Solid-State-Recorder/17765283  

Thanks Jim, good to consider, but way beyond budget.  She only needs to do these a few times a year, but the current mic is very noisy and has terrible fidelity. Really looking to keep it in the lower price range and get reasonable improvement.  If she was constantly doing these I'd definitely recommend a decent mic and interface, but we have cost considerations to balance with the number of presentations she is doing.
 
I am seeing some good reviews on that Blue Yeti USB, but still open to any suggestions on a pretty cheap interface and mic that would be better, based on Jim's notes above.