Save on your watering bills. For example, water in the cool morning hours to cut down on losses to evaporation, mulch the soil to keep it cool and moist, and use a soaker hose to deliver water directly to plant roots.
Also, see if you can have a separate meter installed for outdoor use; metered water for outdoor use is often charged at a lower rate because there's no sewer or reuse charge.
It may be hard to pass up a $7 shovel, but it pays to buy quality tools. Cheap shovels tend to break when you're digging in heavy clay or rocky soil; discount pruners often fall apart when used frequently. Get tools for the long run and you may never need to replace them. It's better than purchasing a new shovel every couple of years.
Feed your plants naturally and improve your soil with compost. For quickest results, use a tumbling composter. Or if you're patient, place your organic materials in a bin or even just a pile and let nature do the work.
Don't bag or rake up grass clippings after you mow. When left on the ground, they'll decompose and add nutrients and organic matter to the lawn.
Exception: Don't leave clippings if you've let your grass go a little long between mowings. Too much clipped grass could smother your lawn.