First, I've pretty much accepted that in order to get a job done or attain my goals, I need to invest either time or money, or lots of both. Spending more time generally means saving money. Spending more money often means saving on time. I seldom find that I can save lots of time while avoiding spending money to do something.
1- I use mulch to reduce watering, thus saving both time and money, but only up to a point. It takes time for me to haul water to the farm, although I have an ag catchment tank. But relying upon the ag tank alone wouldn't last me an extended dry spell. Hauling water not only takes time, but it costs money for gas and wear & tear on the truck. So thick mulches only reduce the amount of needed irrigation. Mulch doesn't totally eliminate the need to water.
2- I use mulch to reduce weeds. Weeding takes up a lot of time. By using mulches, my weeding time is greatly reduced. While making mulch costs a bit of money and time, overall it saves me hours and hours of labor.
3- I don't try to eliminate 100% of the weeds. This saves a bundle of time. The mulch takes care of the bulk of the weeds, so I just basically have to deal with the tropical grass. And rather than trying to dig or pull it out while a crop is growing, I'll either just cut the grass off just below the surface or cover it with a layer of mulch. It's much faster. When I redig the soil between crops, then I'll remove the grass roots at that time.
3- I make my own mulching material. This saves money compared to buying it, but takes up time. And costs money when it comes to buying a lawnmower and the gas. But in my opinion, making my own is a far better deal for me than buying it.
4- I produce quite a bit of my own seed and starts. Because I have a homestead farm, I'd say that I save hundreds of dollars every year this way. If you haven't noticed, seeds are getting expensive to buy. And shipping bulky orders to Hawaii is expensive.
5- I produce my own fertilizer. While this saves me money compared to buying it, it does take up time. And of course, there is that cost involved with the lawnmower & gas thing. But commercial fertilizer is extremely expensive in Hawaii, thus I feel that making my own is a good deal for me.
6- I rely upon hand tools for part of my work rather than gasoline guzzling tools. This also saves on maintenance costs of the gas tools. My soil has improved to the point that it's actually faster to use a shovel on a bed than to bring out the rototiller. The tiller still gets used when it's advantageous, but I often reach for the old shovel. Farming with a tractor can't be done on my land, so that by itself is actually is a major cash savings. No expensive tractor to buy, run, and maintain. But on the down side, it means that I spend more time physically working.
7- I aim to use "better than organic" methods, thus saving on herbacides and chemicals, though they are not totally eliminated.
8- I gather my own local resources, such as lava sand, coral sand, bones, sea minerals. I don't buy my soil amendments. Plus I'm usually in the locale already when I gather inputs, so it's not an extra trip to make in the truck. This may not work for other people, but I've got quite a workable system going that does just fine for my small farm.
9- I repurpose materials. I don't buy much in the way of pots, plant labels, trellis material. I use donated materials, yard sale buys, and cheap stuff to make container gardens, work tables, mini greenhouses, etc. There are certain things that I buy, but I tend to repurpose when feasible.
10- I do much of the labor myself. This is a big cash savings, but uses lots of time. But I see a huge reward in doing things myself. I like doing it. I get a sense of accomplishment......gee, I did that MYSELF!!!!