Danny Seo, environmental-lifestyle columnist and author of the Simply Green book series, recommends these shopping strategies for going green on a budget.

1. Watch your supermarket's sale circular. Stock up on organic products like dry goods and frozen fruits and vegetables when they're on sale.

2. Buy store brands. Many national grocery chains now have their own organic products, which can be significantly cheaper than the name brands.

3. Create a co-op. Get together with friends and neighbors to buy green products in bulk, perhaps online. Cleaning products, compact fluorescent lightbulbs, and many other items can be had by the case for a lot less, and you can buy grass-fed beef by the side directly from the farmer.

4. Shop around. Try discount or low-end retailers for good-quality green products at lower prices.

5. Read labels. Sometimes green doesn't cost more. Method detergent, for instance, comes in a smaller bottle, but it's highly concentrated, so it costs less per load - and thus requires less packaging and less energy to ship.

Not every single manufacturer touting an environmentally sound product has similar grounds for explanation, however. Goldman cites one carpet maker that sells a "green" line of products that cost more than those in its conventional line but aren't much more sustainable. "They slapped the label on and charged more," she says. "It happens."

Then there's the old line item on a balance sheet called goodwill. Upscale brands are able to charge more for their products because of that ethereal, intangible price booster: prestige. Consumers who look for their bamboo sheets at Neiman Marcus shouldn't be surprised that they are more expensive there than the equally green bamboo sheets at JCPenney are. "Take soy candles, for instance," says Danny Seo, an environmental-lifestyle columnist and the author of the Simply Green book series. "There are some fancy-schmancy versions out there for $30, $40. But you can get one at Target for five bucks."

"You're seeing some green products trying to appeal to a totally different group of consumers to position themselves in the luxury market," says Steve French of the Natural Marketing Institute. "They're selling the notion of a full experience, with the fundamental idea that less is more - which is what environmental products should be [about] in the first place."

There are other, more quantifiable variations on the old “you get what you pay for” argument. The state of California created a task force to analyze the costs and benefits of building green, and it found that while green buildings did cost more up front — by an average of $4 per square foot — the long-term savings in energy, water, and waste, as well as the increased health and productivity of the workers inside those buildings, led to a 20-year benefit of about $50 to $68 per square foot. A superefficient washing machine or refrigerator will cost hundreds of dollars more than an inefficient one, but the eventual payback in energy savings is definite. A hybrid vehicle is thousands of dollars more than a nonhybrid, but with gas prices at record highs, it gets cheaper very quickly.

While a pair of recycled-polyester boxer shorts might not pay their buyer back, the production process for the filament used in those boxers is comparatively energy efficient, and the textile company pays less for the raw materials needed for recycled polyester than it would for the petroleum-based chemicals that go into virgin polyester, notes Patagonia’s Dumain. Meanwhile, rising oil prices are pushing the cost for those virgin materials up further. “At some point, there has to be a point of intersection, and recycled will end up costing less than virgin as recycling increases and volume increases and the feed stock grows,” she says. “That’s what needs to happen to take it out of the specialty realm. It’ll take years, but we have to start somewhere.”