Yard & Garden
If you have a small yard use an old fashioned push mower instead of a power mower. You can probably get one at a yard sale for next to nothing, it doesn't use any gas, oil or sparkplugs and as a bonus it's good exercise and good for the environment!
Start your own plants from seed instead of buying them at a nursery. Seeds and potting soil will cost you a lot less especially if you need lots of plants.
Share seeds with a friend. Often you don't need the whole packet and they don't last forever when stored.
Some plants can be grown from the seeds of plants you grew the year before. We know a lady who saves the marigold tops when she deadheads the plants and grows hundreds of marigolds every year for nothing!
Start plants from cuttings. This is easy to do. Just put the cuttings in water and wait for roots to grow.
Get perennials from friends or relatives. People are usually happy to share their plants with you when they thin them out. My sister gave me several varieties of lilies and some beautiful yellow flowers that we think are called "Sun Drops". In exchange I gave her oregano, chives and tarragon from my herb garden and part of a large Hosta that is threatening to take over the yard (or possibly the world!).
Use plants that are native to your area. If you live in the desert grow cacti and succulents, not plants that need lots of water. They will grow better and be easier to maintain. Also consider xeriscaping which uses different materials such as colored stones to define various areas of the yard rather than lots of flowers.
Try to overwinter your hanging baskets. We've been able to keep quite a few varieties alive in our basement under a growlight.
If you don't want to be bothered with overwintering dump the potting soil into your outdoor gardening area...it helps build up the soil. Clean the pots and save for next year. You can buy flats of impatiens, enough to fill several pots, for less than you would pay for one hanging plant
Grow herbs. They are resistant to bugs, many are perennials and they taste way better than the dried ones (that cost an outrageous amount at the grocery store anyway). Many are pretty enough for your flower garden. You can easily dry them for winter use by tying them in bunches and hanging upside down in a dry place in your house.
Unless you really love gardening, don't waste your time and money growing things like zucchini that you know your neighbors will all be trying to unload on you come August anyway.
If you live near a vocational high school with a horticulture department you may be able to get some cheap plants and also some free landscaping.
Buy garden tools, outdoor furniture, barbecue grills and other outdoor items at the end of the season when they are on clearance. Put them away and you'll have brand new stuff for next year!
Buy mulch from a garden center rather than a multi purpose store like Walmart. It will be a lot cheaper. We've been told that the cheapest way of all is to buy a truckload. We don't need that much so haven't investigated the price.
Invest in a compost bin. It will provide free fertilizer for years to come
Buy a plastic cover for your grill. They are cheap and will help your grill last longer by keeping out rain and dust.
And speaking of grills, it's relatively easy to replace the burner in a gas grill if it wears out. Much cheaper than buying a new grill!
Cooking outside helps keep the house cool and saves on air conditioning costs.
From Kasey McManus in Rochester, NY: I was just looking around your site, and had an idea that I myself just found today. My fiance and I are getting married in July and we just bought a house, so we are looking for any way to save money that we can. Our home that we bought needs "curb appeal" as they say. I have found that paying $10.00 and joining the Arbor Day society, you will get 10 free trees that are guaranteed for life. You can pick either 10 spruce trees or 10 flowering trees, and they ship them to you for free. I also know that around my home, most towns give away free mulch early in the season, you have go and pick it up but it is better than buying it at the store for $2 a bag.