Sometimes, especially dairy or cattle farmers, will have old hay bales past their prime, even by a couple of years (which means most of the weed seeds inside are dead) and they’ll give you these for free.
Ask around!
I got several free, five-year-old big, round bales that were half rotted about ten years ago. The farmer actually loaded them up and brought them to me as he wanted the space they were in. Not only did they make great mulch, but their state very quickly broke down on my flat garden area and really improved the soil.
“old hay bales past their prime” bkmk
Mine are all free - it’s part of the ‘rent’ he pays us. ;)
But, good suggestion on the straw for everyone - FREE is GOOD...especially when growing food and flowers! :)