Once you get a raised bed made and filled, maintenance is low. After a few years they only subside about an inch a year, and that is easily made up each fall w/leaves and horse manure or compost on top (they hold the leaves down and help them rot). You just pull the weeds and old plants out easily, as the soil you have created is so light and fluffy. Quack grass is my main foe, other weeds don't make it under the raised beds.
Fortunately it is much easier to scrounge garden materials than firewood. Most municipalities have free wood chips, some even have free compost. Both work well in raised beds. I would put the wood chips on the bottom, and be sure to put something with more nitrogen on them, like manure or coffee grounds. I brought home my first bag of other people's leaves today, while I was out shopping in my tiny car. I usually get a few truckloads each fall, for my raised beds and to stockpile for mixing with the old produce in my compost piles. Used coffee grounds, animal manure, grass clippings, lots of these things are easy to obtain. Just lift the grass clipping and leaves in their bags at the curb. Old fruit and veg seems to be particularly nutritious, but that may be harder to get. Ask at a local farmer's market or ?
My raised beds vary from about 8" to 15" tall. I use exclusively free materials for them, with the exception of screws to hold lumber together. 3 raised beds are plastic children's pools with small holes cut into the sides for drainage. One bed is literally that, an old waterbed frame I scavenged from a friend's burn pile. One is random scrap lumber, another is from some hinged boards that were support for something packed on a pallet, a friend saved them at work for me. The best one is the wood that formerly went all the way around playground equipment at my brother's former house, the new owners didn't want it. Another is surrounded by concrete bricks. Got everything from friends or on freecycle or people's trash.
My garden is phenomenal. This year many friends reported trouble with tomatoes, some kind of blight, but that barely slowed mine down. Last year I had a really impressive eggplant yield from 3 plants in a raised bed, while the control in regular dirt had one eggplant. We have clay, not from developers stealing topsoil, but because we are on a slight slope. The neighbors down the road by the river got most of our topsoil years ago.
No tilling means no fumes, no buying fuel, no compacting the soil with heavy equipment. Tractors and things are needed for large scale crop production, but for family sized gardens they are best avoided. If you have nice decomposing mulch, why till it in? Air, water, worms, bugs, and roots will mix it for you without compacting the soil. No-till is an increasing trend in gardening, since it lets the soil fungus develop that helps spread water and nutrients to your plants' roots, plus doesn't disturb the air and water channels that develop over time.
