When grocery shopping on a budget, it's a good idea to go to the store with a list instead of relying on memory. Knowing precisely what you need keeps you on task and away from frivolous extras. Likewise, before you plant a single seed in your yard, come up with a plan of action. The notion of having a backyard koi pond surrounded by lush vegetation may appeal to you -- until you research the accompanying price tag. Gardening books and Web sites are smart places to search for initial inspiration. Or take a stroll around your neighborhood or local botanical garden to see what other gardeners have created and take note of what appeals to you.
Chances are, you'll want something that fits smoothly into the surrounding aesthetic. A bright, tropical-style theme might clash if you live in an older, more traditional neighborhood. Perhaps a lush urban oasis or English garden might suit your house better. Think loftily at first, and then tally up the hardscaping and softscaping expenses required to make that vision a reality. From there, you may have a better idea of what you can practically afford.
Hiring a landscape architect to design a garden may be out of your price range. But if you can sketch out an idea of how you want to landscape, you can arrange a consultation with a landscaper for a couple hundred dollars. Some specialty nurseries may also have knowledgeable staff who can offer free advice on the best types of plants to achieve your desired layout.