I saw some videos of people using a bag of garden soil - just on the ground with an X cut in the top, a few holes poked through the bottom of the bag with a screwdriver - seeds or plants set into the soil and watered....it was a survivalist type of video but the garden took off like crazy and the roots found something to grow toward. I’ve also seen the hay bales used with a small area cut out and soil put in there - pretty amazing for those in bad soil areas
We use hay or mulch out here, too-but we put it over the soil around the plants in the curbed gardens to keep moisture in and invasive plants out-cuts down on the time spent raking out weeds. I also use landscape fabric-it is cheap and effective.
Mulch is cheaper than hay here-it is sold for less than $20.00 the pickup load at the fire station. Hay is needed as feed for livestock, so it is more costly.