Hmm. Cheapest way possible is to plug the mic that came with the computer into the mic in on your soundcard and click start/programs/accesories/entertainment/soundrecorder and then click record. Of course it will sound cheap because it was, basically free. You'll find there is a correlation between what you spend and how good it sounds. The more you invest in equipment the better your recording will be. The most important investment if you are serious about learning to record is your time. Using good equipment will get you only so far. It's your knowledge, technique,understanding and talent that will affect your recordings the most.
Besides all that crap, there are freeware and shareware programs on the web(use google) that you can use for now to do some multi track recordings. Do some searches on this website to learn how to record drums and guitars. There is tons of info here for you to learn. Just read, read and read some more. It's free and good luck.
), but if quality isn't your number one priority, then you should probably keep in mind that you or your friends might have a lot of the stuff you need to make some basic recordings. For example, you don't need to get a mixer if you have a PA head that will work just fine. Vocal mics can be used for drums (it won't sound too good, but if it's just for fun, who cares?), and if you have some type of basic amp modeler (like a Digitech pedal), you could easily record directly into your computer for mediocre sound. Of course, the better you want it to sound, the more money you'll have to spend. One of the worst newbie (and yes, I'm still a newbie) mistakes I see is people with no expieriance who go and spend $5000 on some fancy digital recording console, and then do the same things they could be doing with a $100 mixer simply because they don't have the expieriance to utilize the fancy equipment. My suggestion is to just start with some basic equipment, figure out how everything works, and slowly work your way up. At the very least, you'll gain expieriance that will help you infinately in the music world (I know I've learned to make my live rig sound 1000x better since I've started recording). So don't worry about blowing too much money at first, don't get discouraged if it doesn't sound good, read these forums, post on here if you need anything, and most of all have fun with it.