Here we have a review of the Fifine K034 USB microphone. We put this to the test and actually recorded guitars in a mix to see how it would sound. All guitars were recorded with this mic.
This would be a perfect solution if you don't have the money to throw down on an interface for recording instruments.
You can purchase this mic here...
https://www.amazon.com/Fifine-Microphone-Selectable-Frequencies-K034/dp/B073JLFYX8/ref=sr_1_1?ie=UTF8&qid=1503177808&sr=8-1-spons&keywords=fifine+K034&psc=1