Mulches can either be organic or inorganic. Organic mulches, like pine bark, break down over time. Inorganic mulches, like gravel, will not be broken down over time. Mulch is used for compost material or for aesthetic value in the landscape. It's also used to preserve moisture and to keep plants from washing away. While there are varying types of mulches, each offers a different advantage.
Leaves are organic and will break down, providing nutrients to the soil. Leaves can be ranked from your yard and used as inexpensive mulch. This mulch type quickly decomposes and will eventually turn into compost.
Inorganic material like pebbles and gravel will not break down over time in the garden. They provide no nutritional additions to the soil; however they can often look neater than other mulches. Stones also provide a decent weed barrier, especially if they are placed over black plastic.
Shells from beaches make lovely mulch that works the same as gravel but gives an entirely different look to the landscape. Shells won't provide soil additives and they are quite expensive. Using shells as mulch is far less common away from coastal towns.
Pine bark and pine straw are both organic mulches that can come in many forms for use around plants. There are pine bark nuggets, ground pink bark, large pine bark strips and pine straw. Pine mulches won't wash away like some other kinds. Pine mulch can be easy to get depending on your surroundings. Check with lumber companies in your area or use a wood chipper on fallen limbs from your backyard.
Scatter the fine scent of chocolate throughout your garden with cocoa shells. Cocoa shell mulch will need to be watered to use as mulch so that the pieces can bind together and not wash away. This mulch is better for landscapes without pets, as they can become sick on the hulls if they chew on them. Cocoa shell mulch is moderately priced.
Used ground coffee or whole coffee beans can be picked up at local coffeehouses (they usually save their used grounds for this purpose). While it will give the garden a rich coffee smell, it also is organic and adds nutrients to the soil. It's not a very long lasting mulch, but a nice-looking one.