"What?" I hear you ask. Yeah, you probably already have a home music studio. Do you have a computer made in the last 10 years? Does it have a sound card? Do you have access to the internet? If you answered "yes" to all those questions, then yup...you possess a home music studio in your home.
Most people have some form of microphone these days, whether for VOIP chat, on-line gaming, making quick videos on your computer of yourself singing European pop songs;), video blogging, etc. However, if you don't have a mic yet, I recommend you pick up a $59 USB micropohone, like this: Samson Q2U USB mic, and you'll definitely be on your way.
The next question becomes: "What kind of music do you plan to record?" That will determine much about how you approach things. For example, if you play electronic music and plan to use lots of midi, there will be more gear and software needed than someone who simply plans to record themselves playing a guitar and singing. I'm going to briefly describe that latter scenario.
If you have always wanted to record your music, but just didn't know where to start and didn't want to spend the money on a professional recording studio, what I'm about to say should please you.
In this day and age, it is possible for a total newbie to start doing multi-track recording ("layering" tracks, like guitar on one track, then singing along with that to put your voice on another track, etc. ad nauseum) with the tools I described above.
Simply download the open-source home recording software called "Audacity," plug your mic into your computer, and you are ready to rock. I poo you not.
Yeah, you'll have to learn to use Audacity, but the web is filled with free tutorials for that. Home Brew Audio has some of the best ones (if I do say so myself;)). But the point is that it doesn't take long to learn the basics in Audacity.
Once you do that, you can do things like record a song with you (and or your band/buddies) playing rhythm guitar on one track, lead guitar on another track, piano on a 3rd track, flute on a 4th track, lead vocal on a 5th track, harmony vocals on tracks 6-15, etc. And you can do it a track at a time, which is awesome. That means you can all the above yourself if you are so inclined. The magic of multi-track recording is amazing for a musician.
Anyway, now you know. You almost certainly already have a home music studio in your possession. Cool huh?