Peat moss is a sustainable soil amendment that is harvested in Canada. Currently, less than .02 percent of the peat bogs in Canada are being harvested for horticulture, and it grows back at a rate of 60 times what is harvested. That makes peat moss a guilt free mulching option.
Peat moss is also quite inexpensive. You can buy a large bale at the garden supply store for about $10, and it will go a very long way for most home applications. The bales are very tightly compressed, and expand to about twice their size when opened, so you get a lot more than it seems at first glance.
Peat moss can be applied liberally as a top dressing to any soil, or tilled in if you prefer. Using it as a mulch means layering it over the top of the soil, which helps it to do its job of gathering and releasing existing nutrients in the soil, while helping to retain valuable moisture.
Combining peat moss and organic compost will create very favorable soil conditions to help you make the most of your lawn or garden. You will also get the benefit of needing less water, because the peat moss will help prevent evaporation.