After weeks of delays, the network television upfront is kicking off in earnest today, with most buyers saying the vast majority of deals will be wrapped up by the end of the week.

When it's over, the networks will likely have sold about the same amount of inventory as last year but with prices somewhat down from last year's.

As of a week ago, it looked as though the networks would succeed in holding out in their demand for price increases for advertising for the coming broadcast television season. But as the week wore on their resolve faltered, and the sense was that buyers would succeed in driving down prices after all.

What caused the shift was yet more dour economic reports, scotching expectations that the ad economy would improve as the year went on.

This broadcast upfront has dragged for weeks since the networks’ fall previews to buyers in mid-May, the longest delay in memory, and much of that was because reluctance on the part of advertisers to commit millions of dollars in an economy stubbornly stuck in recession.

“Business is slowly getting written,” one buyer told Media Life on Thursday, ahead of the long weekend. “A lot of the holdup was that budgets weren’t registered. Now they are, which will get things started.”

The networks had been asking for low-single-digit percent increases in cost-per-thousands, the cost to reach 1,000 viewers, and many thought they would get them, but the latest reports on rising unemployment and sinking consumer confidence had the effect of shifting the balance toward buyers.

With the weaker economic outlook, the networks lost their key point of leverage: the option to hold back inventory for sale later in the year in the scatter market, where inventory not sold in the upfront is auctioned off.

Holding back inventory only makes sense if the economy is likely to improve in the near-term, boosting advertiser demand--and the prices that inventory can fetch in the scatter market. If the economy is not likely to improve the networks face the risk of that inventory fetching even lower prices.

The outlook now is that upfront pricing will fall somewhere between the increases the networks were asking for and the steep price cuts buyers were demanding.

Overall, prices will be slightly down from last year, with NBC likely to see sharp declines. ABC and Fox will likely see slight decreases and CBS, the only network to post ratings increases this past season, will probably see prices come in about flat to last year or slightly up.

“For the budgets that have been registered, the networks are seeing that volume is indeed down,” says a network negotiator. “They’re coming around. I expect prices will be down, although it will be a range.”

There are a couple of big questions still looming in the upfront, which will determine how much spending is down from last year’s roughly $9 billion.

CBS has been quiet about its plans. A few buyers think CBS will ask for and probably get price increases.

Moreover, it’s unclear how much inventory the networks will sell.

Typically, when networks are confident the economy will improve they’ll hold back inventory to sell at higher prices later on. The networks’ concern is how much they sell by the end of the year, not in the upfront.

CBS almost always says it will hold back inventory, although it rarely does.

With the economy showing few signs of recovery, outside a few indicators of a rebound like the leveling off in home prices, it’s unlikely the networks will gamble on prices rising later in the year.

“I don’t see a strong marketplace until the first half of 2010,” says this network negotiator.