I bought the SFG book in January and have built two raised beds out of basic lumber from Home Depot. The 1/3 of each material is the way to go. It is a bit pricey up front but it's 100% worth it. We've had drenching rains that would normally waterlog the ground and disrupt root supplies of plants before, but even with 3 straight days of rain, the soil remains friable and drains extremely well.
After you get started and make the $100 investment in composted soill, vermiculite, and peat moss, start your own compost. It's really easy to do. Any garbage can can be used as a "pile" and will provide plenty of good "fertilizer" when complete and can even be used as mulch in two-three weeks.
Every other ways requires way too much calculation and constant additions of nutrients that can burn your plant in a heart beat. I just recommend staying with compost since it will slowly release nutrients and is in a good balance as it is.