Mulch is a gardener's best friend. It is organic material, usually made of old vegetables, wood chips, straw, leaves or sawdust that is used on top of soil to protect the soil and the plants growing in it from inclement weather. It also provides nutrition to the soil and therefore helps plants grow better. You can spend upwards of $40 per yard of mulch with delivery and installation, or you can save yourself quite a bit of green by making it yourself or finding it for free.
Start out by calling a tree cutting company and asking if it's cheaper for them to give away their wood chips to you instead of paying to take them to a landfill. If that doesn't work, call your local landfill to see if they have any usable debris that homeowners and landscapers have discarded that you could be turn into mulch for your garden. You should also check on Craigslist for mulching materials and firewood that people are giving away for free. Or you can make your own mulch by composting the fallen leaves from trees on your property with organic scraps from your kitchen (no meat or dairy products). But make sure you confirm that your tree leaves can mulch successfully before you start. Pine needles, for example, work especially well to prevent weeds and most grasses from growing. Eucalyptus leaves, however, produce a chemical that inhibits other plants from growing nearby and can kill your garden.