Agree with most of what has been said - Additionally...
I think the Behringer small mixers are a nice way to record mic to computer. A couple of additions to what has been said so far:
1. The smallest Behringer Eurorack mixer *DOES NOT* have phantom power. Dynamic microphones do not require phantom power. Condenser mics do, for the most part.The smallest model is the "502' which costs about 35-40 bucks. The next one up, the "802" is only about $15 more. I would go that way. (I have both.) In terms of quality, Dynamic=lower quality, Condensor=high quality, generally speaking.
2. Some headphone mics are condensor mics, but still don't require phantom power. Phantom power sends juice to part of the mic to "energize" that part of the mic that pics up the signal. The largest studio mics have a completely separate power source, smaller mics (but not all headphone mics) that are condensor require phantom power that comes through the XLR (large 3-pin) connector. Many, but not all, headphone mics, due to the small size of the mic's surface area, are "pre-energized" at the factory and require no additional power (ever) to work correctly. They are still condensor mics, technically, but unlike larger mics (handheld for instance) do not require phantom power. Check the spec sheet for the microphone.
3. Depending on your set-up, another thing you may need is a "direct box." This little gem can remove a common "Humming" sound that often intrudes from the electrical system if you have a lot of mechanical junk hooked up to your electric system and the grounding of the system is not perfect for recording. If you need this (and you will probably be able to tell quickly that it is a problem) you can buy one at a music store, like Guitar Center. The feature you need is actually called "ground lift." which is only one thing that a direct box does, but the other stuff may not matter to you. They can be bought for about $25 bucks.
4. Using the "audio in port" on your Mac may produce mixed results. They are known to be "noisy" and you may start to notice it when you have better equipment up to that point. Additionally, some Macs have no audio in port (like mine.) You may find you need a USB audio input device. I recommend the Griffin Powerwave. I have others, but they require buggy drivers to work and the Griffin does not. Believe it or not, a decent USB to audio input can be better quality than the audio in port. Plus I hate using mini-plugs for anything due to their fragility and unreliability. IMPORTANT: you CAN NOT plug a USB audio input into a HUB or keyboard, etc, of any kind and just expect it to work. It can be highly unreliable and flaky hooked up that way, because sound is streaming and constant and hubs work with packets of information, so can destabilize the signal. GRIFFIN has created a hub engineered to work with audio devices properly. It is available from them and is reasonably priced. They (Griffin) can also be a great source of advice on hooking up their equipment to other pieces. Smart, friendly people.
All of this is general info, of course, and your experience may differ...