I reuse labels from my orchids. They are stronger labels too. Paint stirring sticks from the paint store are really good for labels.
I use the spent orchid mix and soil that is not good for the garden any more as fill in low spots in the yard. The old orchid bark I use for mulch. I still bleach them first to kill as much of the bacteria and fungus I can on them.
I buy in bulk fertilizer, peat moss, perlite from an agricultural wholesaler.
By mixing my own potting mix, I get the mix I need for my plants whether I am growing cactus or watercress and it ends up cheaper than buying ready made potting mix.
I have turned old bathtubs into water gardens, broken wheelbarrows into planters. Wine boxes and coolers into planters.
Grape containers from costco into mini greenhouses
Buckets from restaurants and bakeries for planters. Sometimes they sell the buckets but the gallon cans are free for the asking. 50-55 gallon drums usually at a reasonable cost make good rain barrels or half barrel planters.
To save on watering, I group plants that need more water around the sprinklers but hand water other plants on scheduled days.
Free mulch is available from the local recycler and some other places if you pick it up. The electric company will dump a truckload of tree trimmings if you ask for it and they are in the area.