Baled straw or hay happens to be a fantastic organic material to use as a mulch which then becomes lunch for the earthworms and soil microbes. It is generally available in the country and the exurbs and can be found at stores selling horse riding equipment in the suburbs.
The problem with straw or hay is that for most folks it does not look very good on a flower bed, or under trees or shrubs. And that is true; it is an ugly mulch. One trick to take advantage of this excellent relatively inexpensive organic material is to run the hay or straw through a chipper shredder. Now we have small bits of hay or straw that make a neater mulch is terms of laying flat. Then to address the aesthetic limitations, you can add a half inch to one inch layer of your favorite bark chips or shredded bark. The three inches of shredded hay or straw are chow for the soil critters while the chips keep the yard looking neat and tidy.
In The Vegetable Garden
Hay and straw is a standard mulching material in the vegetable gardens of America. In these gardens, for whatever reasons, the material looks fine to most folks; it is not an ugly veggie garden using hay or straw mulch. We keep three to four inches of straw over all of the beds in our vegetable garden 365 days a year. By the end of the season, we usually have to add some straw which by then might have settled down to one to two inches as the earthworms do their harvesting.
For more information about mulching the vegetable garden go to the file Mulching The Vegetable Garden