Comment: Depends on if you can get

mulch materials free or cheap or not. This is what I used:
sawdust from local saw mill: they load it into pickup= 5.00 lasts me at least a year.(I have alkaline soil, so it helps it, but if you have acid soil, it may not).
straw bales, I bought 20 bales at 2.00 bale. enough for year, in garden, for making container for putting cabbages in over winter, and bedding for the chickens.
Pine needles raked from around trees: free
3.4 cu. ft. bales of peat moss. I use two or 3 a year, for lasagna gardening and for starting seeds in my sun room, about 15.00 each.
You could beg neighbors for grass clippings, or get them at the dump., beg for leaf rakings, etc.
Go into woods near you and rake for mulch.