Mulch offers several benefits to the home gardeners, so its worth the effort of spreading it around. It suppresses the growth of weeds, which makes maintenance much easier. It helps the soil retain moisture, which reduces the need for watering. And it provides a steady source of nutrients for the soil, which are added at a slow rate as the bottom layer of mulch slowly decomposes. Standard mulch can be expensive, but you can get the same benefits by using a variety of other materials that will have the same beneficial effect.
Landscaper's fabric is a thick, mesh-like fabric that is sold by the roll and does a fabulous job of helping to suppress weeds. It is often used in vegetable and herb gardens to cover areas in between rows. It can be cut to shape to fit perfectly into any flower bed and fit snugly up against the stems of growing plants. The best way to use landscaper's fabric as mulch is as the bottom layer: put it down first, tucking the corners down into the soil a bit, then cover it with a layer of mulch or one of the mulch alternatives listed below.
For an even more cost-effective bottom layer, newspapers will do the same job as landscaper's fabric. Simply save your newspapers over the course of the winter, then spread them out in a thick layer over the area to be mulched; hose down until they are thoroughly soaked, then cover with a layer of mulch or mulch alternative.
Any type of small rock or pebble, applied in a thick layer, will help to suppress weeds and retain moisture. Rocks or pebbles, of course, don't have the same beneficial effect of supplying nutrients but they are neat and economical. They look especially nice with modern architecture or minimalist landscaping.
Pine trees provide an abundant supply of natural mulch alternative. Simply collect the dried pine needles from beneath pine trees on your property, or ask around. Many homeowners with a few pine trees would be happy to share their wealth with you. Pine needles can be rather acidic, so take care on plants which need a more alkaline soil.
If you have a lawn, you have a free mulch alternative. All you have to do is collect your grass clippings and pile them up somewhere unobtrusive; give them a few months to dry out, then apply them as mulch. They can be a bit messy looking, so they are an ideal choice underneath larger shrubs or trees with low-growing branches which will provide a bit of cover for the grass clippings. Damrosch cautions in "The Garden Primer" that grass clipping decompose so rapidly they can burn herbaceous plants; you can still use them, but be sure they aren't touching the stems.
Purchase hay or straw by the bale from local farmers and use it as an inexpensive and sweet-smelling mulch alternative. It offers all the benefits: weed suppression, moisture retention, and nutrient release. It works well in the vegetable garden or wherever larger areas need to be covered; it is probably a bit casual for the front flower bed, but you can always cheat by applying a thick layer of hay as your primary mulch and covering it with a thin layer of more expensive and more attractive mulch as the top-dressing.