Last night, I heard a financial expert fretting that Obama’s $300 million proposed tax cut “wouldn’t work,” because Americans might not spend the money. What are those cheeky tax payers planning to do with their rebates? Pay off credit card debt? Save? Heretics!

By January 1, 2010, I predict the Dow will be around 7,000. It still has a few humps to get over. For the duration of 2009, the American people will continue to adapt to these new challenges. Are they going to stop shopping? No. But they’ll shop less and they’ll shop smarter.

That means there will be an enormous surge in the market for secondhand goods. Though there’s a strong stigma against giving “previously owned” Christmas presents, this year there were long lines at Buffalo Exchange, a Manhattan consignment shop. The privately owned company has grown to $50 million in annual revenue.

"I think that people are more willing to sell their clothes when the economy's bad,” explains Buffalo founder Kerstin Block, “and they're more likely to shop in used-goods stores."

A sustained economic downturn amplifies both supply and demand for the used-goods market. People are motivated to convert unused items into cash, and buyers are actively searching for radical discounts.

One company set to benefit from this trend is eBay (EBAY), which referees a massive marketplace dominated by used goods. They also own PayPal, which was a synergistic acquisition. It has a market cap of $18 billion, a P/E ratio of 10, revenue of $8.6 billion, and an operating margin of 25%.

The stock is currently trading at $14.77 - a 55% discount off its 52 week high. 2009 is going to be a good year for eBay.

If you’re looking at the big picture, and you care about this country, the fact that Americans are spending isn’t necessarily good news. The fact they’re spending smarter is.