Home production software means that almost anybody with an ear for music can make professional sounding compositions at home on a computer. All you need is the patience required to learn how to use the software and the money to pay for it. Basic but functional programs are available relatively cheaply but if you don't want to fork out for one of these, there are a number of ways you can produce music for a backing track for free.
Navigate to an online service that allows you to make music for free, such as jamstudio.com, soundjunction.org or buttonbeats.com. (See Resources.)
Sign up for account and log in.
Start writing your backing music.
Record your piece. Some services allow you to use your PC's microphone to record vocals.
Export your backing track as an audio file when finished.
Borrow some musical instruments from friends, family or colleagues.
Write your backing track.
Position your cell phone close to your instrument.
Activate your phone's voice recorder.
Perform your piece and then connect your phone to your PC to export it as an audio file. Repeat as necessary with other instruments, then use free online audio editors to mix your backing track.
Contact musicians and studios and tell them about the piece of work that you need to record a backing track for. Try to persuade them that it would be worth their while letting you use their recording equipment and perhaps collaborating on your backing track. Offer a credit in your finished work as compensation.
Write and record your backing track once you've found an agreeable party.
Add the names of the owners of the equipment that you recorded your backing track on to the credits of your work.