It’s officially under way, the Hamptons marathon, the annual January kickoff of the summer rental season in one of New York’s most popular vacation spots where you can mingle with the rich, the famous, the infamous, the up-and-comers, and the wannabees.

Take your pick – Southhampton, Easthampton, Westhampton or Sag Harbor. They’re all part of the increasingly popular Hamptons scene, where the average home rental, I’m told by Diane Saatchi, regional voice president of real estate biggie Corcoran Group, runs about $50,000 for the summer season (Memorial Day through Labor Day) and roughly $10,000 to $20,000 for a two-week stay during that period at a residence that’s guaranteed to impress the dickens out of your friends.

Needless to say, the closer you are to the water with oceanfront property, the more you’re going to have to have to dig into your wallet.

Rentals, of course, run a lot higher for the premier estates, notably those in Easthampton and Southampton. For example, Denise Rich’s former Southampton estate, which she sold, holds the season’s rental record at $500,000.

Clearly, initial activity in Hamptons rentals is not what it used to be, Ms. Saatchi tells me. Going back five years, 30% to 40% of the rentals would have already been spoken for by this time, she said. But now, she added, people seem to be increasingly concerned about spending the money and they’re delaying the start of the shopping season from late winter to the springtime.

She attributes this year’s slower than usual start to several trends. Chief among them:

* More rental customers have become owners because of low interest rates. Sales, for example, were up 10% in the third quarter, followed by an estimated gain of more than 15% in the fourth quarter. For all of 2004, reckons Ms. Saatchi, Corcoran’s expert on the Hamptons, sales were up about 15%, versus a year-earlier.

* Many buyers of Hamptons homes stretched themselves financially to make the purchase and refurnish the houses and are now being forced to rent them out, putting a lot more inventory on the market.

Apparently, the abysmal start to the 2005 stock market is already taking its toll. I’m told that one worried Wall street trader, whose 2004 bonus was also not what he thought it would be, backed away from a $240,000 season rental. In the process, he lost his $35,000 deposit.

A top broker at Allan M. Schneider Associates, which is already out with its brochure on 2005 summer rental properties in the Hamptons, describes the early rental business as “disappointingly slow.” Renters, he said, are notorious bargainers, and some have been demanding – and getting – even at this early stage, some deep discounts from the asking prices.

A couple of plusses for the owners, he feels, is the weak dollar, which is likely to encourage more rentals from foreigners, and the unwillingness of many Americans to travel overseas because of fears of terrorism.

New Yorkers normally account for about 90% of the Hamptons rentals, with the West Coast representing an other 5% and overseas and other American areas making up the remaining 5%.

Meanwhile, if a vacation in the Hamptons is your cup of tea and you can ante up the rent, the Corcoran Group will be pleased to show you a Southampton estate with all the trimmings- eight bedrooms with eight baths, a custom-built gourmet kitchen, a heated pool and pool house, and a tennis court – all set on 2.8 acres with private ocean beach access. For the season, the asking price – that’s before any bargaining – is a mere $450,000.

Too much, you say? If that’s the case and you want to save a few bucks, you can rent it for just about a month – August through Labor Day – for only $17,000. If that’s still too rich for you, try Westhampton.