OK, assuming you have a Mac with GarageBand, here's a trick and it's totally legal... OK, it's legal but it's a little edgy...
Go to every loop site, start with acidplanet and look at the various CD collections they have posted. They almost always give away 5-10 sample loops of percussion, basses, etc. Download every loop you can find. If you can go on Ebay and actually buy a loop library that you like so much the better.
OK, now you've got 30-40 loops to work from. Maybe you got lucky and found a drum beat you like. Open a garage band project and set the tempo to your songs speed.
Drop one of these loops in and copy and paste it across the track. There's your drums. If you're really clever, you can cut this one loop up a dozen different ways and makes fills and transitions out of it.
Use a bass from the instruments and lay down the bass track.
Find some other samples for the rest of it.
No matter how cheezy your project sounds, FINISH IT! You'll learn all kinds of things about arranging and song writing but only if you actually FINISH IT! I can't stress this enough.
Good luck and may the inspiration and magic be with you.