There are mics that have a USB cable, are their own sound card*, and pull the phantom power from there. But I've never seen one that was really recommended for recording instruments. They are all targeted at podcasters, and recording speaking voice.
Yeah, a USB mic can get you started for cheap, but expect to throw it away if you want to progress any further than recording a single track without monitoring.
*There's another problem with this, USB mics are a soundcard with just an input and no output. This is fine for Windows sounds, but if you end up using a more professional piece of audio software, it is highly recommended that all the inputs, and outputs are on the same interface. The biggest problem is latency for monitoring. If the audio is going into the mic's interface, being processed by the computer, and re-output from another interface, there's no way to minimize the round trip time (professional audio interfaces have local monitoring, that sidesteps the computer completely), and what you hear in the monitors (headphones) is delayed enough that it makes it difficult to play/sing correctly. The other less noticeable problem is clock skew, but that only really applies to combining the input from multiple interfaces into one recording.
Pioneer VSX-1018AH-K, PDP-5020FD, DV-79AVi
Axiom M22s, VP150, QS8s
Sony PS3, surround backs