I don't remember where, but recently I read about the greatest cheap and lazy method of making a garden bed that involves nothing more than laying down newspapers to smother the grass and dumping a bunch of mulch on top. I wanted to plant some stuff along the side of the house to mitigate the ugliness of the air conditioning unit and eventually shade a few windows, so I decided to try it.
Seriously, it's fantastic. I don't even know if it's going to work yet, but I'm all about it. All you need is like thirty bucks' worth of mulch--free if you want to make your own, but I don't--and a ton of newspapers. In that case it is nice to know a sympathetic archivist who is nice enough to rescue a bunch from her library's recycling bin.
After you have assembled those two things, you just lay the newspapers over the grass and weeds, several sheets thick, overlapping them so no weeds can poke through. The news has been pretty bad lately; the garden will grow amid stories of lost fortunes and furious primates.
Then you soak the papers with the hose so they won't blow away and will break down more quickly, and spread a few inches of mulch on top.
That's all. It took ninety minutes, thirty dollars, and the kindness of a friend to make 100 square feet of plantable space. You're supposed to let the whole mess break down for a season, but fuck that. I'm trying for scraggly bushes, not prize-winning orchids. Luckily, you can just punch holes in the newspaper and dig underneath whenever you're ready to plant.
Stay tuned. It could be a beautiful garden. It could be a bed of death.