it depends on what you juice and where you get it. you can buy bulk organic carrots for pretty cheap, the 5 pound bag costs less than $1 per pound, and the 25 pound bag even less. a few carrots, one apple, some chard and the juice from a half of lemon makes a wonderful juice, and doesn't cost much either. farmers markets are another great way to get fresh inexpensive produce. and as i posted below you can always wildcraft free dandelion greens!
juicing not only gives you lots of readily assimable minerals, but lots of enzymes and vitamins to boot. its really the best thing i have ever done for my health.