the Self-Sufficient-ish Bible, and quite a few websites, we decided to build raised beds. Here are materials you'll need to build one raised bed: 3- 8' by 2' by 3" pieces of wood, saw, long screws, a drill, and lots of soil. One bed ran us about $90; the soil was the biggest expense.
First, we sawed one of the 8' by 2' pieces of wood in half thus making 2- 4' by 2' pieces of wood. Kyle is doing his finest Barney Stinson impression as he models the boards.
What is your garden like? Do you have containers, raised beds, or just a plot of land you've planted?