Patagonia took a hit to its profit margins in order to keep prices for its T-shirts and pants down-to-earth. Over time, the company became more efficient at working with the organic material and managed to get its margins back to normal while still keeping prices reasonable.

Organic, recycled, sustainably produced, energy efficient ­- these are words we're hearing often these days, now that green is, as they say, the new black. They're also buzzwords that lead people to expect higher prices.

But buyers are not necessarily thrilled at the price premium. In fact, sometimes the difference is regarded cynically. Of course it costs more, the doubter sniffs. It's trendy.

Patagonia's recycled-polyester saga is instructive, though, in that it reveals a few good reasons why it can be more expensive to buy an environmentally friendly product than one that is not. Many green companies are smaller than their conventional counterparts, so they lack the buying power and economies of scale that can bring the cost of materials down. Their components may just be more expensive, period - like sustainably grown, fair-trade coffee beans or the hybrid engine in a Toyota Prius. And the simple laws of economics help too. Once other apparel manufacturers start buying recycled-polyester fabrics and organic cotton, for instance, production will go up and prices will go down for everyone.

"Supply and demand," says Nicole Goldman, an interior designer in Cape Cod who's opening an all-green building-products store this month. "For years, solar-slash-photovoltaic was very expensive. The market was so small that only a few suppliers made it. Now it's matured as a product. We'll see the cost come down because demand is up, so more people are willing to produce it."