Last year I spent a considerable amount of money on annuals for the flowerbed, as well. I didn't spend a lot at any one time, but over the course of the season, $5-15 at a time adds up. This year, I'm going to try to start most of the flowers for the beds from seed, as well.
I know we'll use almost as many tomatoes as we can produce. Likewise, cucumbers, bell peppers and any greens we manage to grow. So, I almost can't overplant those items. Even if I did, nobody ever turns down fresh produce, so it wouldn't go to waste. Corn didn't do well last year, and I'm not sure we're going to try it again this year, given the fact that my garden time will be so limited by school.
Potatoes in barrels, as seen here: http://www.weidners.com/spud_Barrel.htm, are definitely a repeat player in our garden, as are sweet potatoes. Sweet potatoes are ridiculously easy to grow: http://organic-vegetable-gardens.suite101.com/article.cfm/growing_sweet_potatoes, and they're attractive enough to be used in the flowerbeds.
Even if you don't have a lot of space, or aren't able to handle physical labor, you can raise enough food to supplement your diet AND see a savings on your grocery bill. Here's a site that describes a very easy (yet successful) method of raising some of your own food: http://www.no-dig-vegetablegarden.com/index.html.
Raising your own food (or supporting local farmers by shopping at your Farmer's Market) is good for you, good for your family and good for the environment. Here at Clay Hill we do both - I raise what I can, but nothing beats Saturday morning browsing the Farmer's Market - I just wish our local markets were bigger! Maybe next year (after I've finished school!), we'll put in an extra bed or two for the market - that way we'll contribute to making the market more successful and I'll get my Farmer's Market fix!
If you're a fellow gardener, are you planning your plantings yet? And, if you're not a gardener, maybe this is your year to change that. Consider planting a tomato or two in a container, if nothing else. Our local nursery sold tomato plants last year at the bargain rate of $1.50 for a pack of six - those plants could potentially supply a family with all of their salad and slicing tomatoes for the summer. One bite of a sun-ripened tomato, and I guarantee you'll be hooked on gardening!