If you need weed control in a tree and shrub garden, the large bark chunks have been shown in research to keep weeds from sprouting because they don't offer enough fine surface area. However, the big bark chunks break down very slowly and don't suit flower and vegetable gardens where one of the purposes of mulch is to improve soil quality as it decomposes. These mulches resemble crumbled chocolate cake and they enhance the flower and vegetable garden while breaking down to add humus to the soil. Two to three inches of these, or of home made compost, provide a good fall garden addition. They can certainly also be used for all landscape areas where mulch is desired.
Some mulches take time but are basically free.
My favorite is made from fallen leaves, bagged and tucked away for six months or longer. I suspect it was, decades ago, dug from the layer of fallen, decayed leaves in forests surrounding large estates. Troops of gardeners with wheelbarrows may have harvested it from the woods as part of their garden work. It's soft, crumbly, and the individual leaves aren't recognizable. The fragrance of leaf mold is pleasant and mild.