The traditional autumn season for selling new homes has begun. But after 18 months in which new-build levels fell to unprecedented lows, those who were expecting bargain-basement deals might be in for a surprise.

Developers have had to lower their prices, but Knight Frank, the estate agent, estimates that prices for new-build houses are only 15 per cent off their 2007 peak, having bounced back about 10 per cent since the start of this year. Prices for new-build flats fell more steeply and are still down by about a quarter, but many agents and developers believe that the time for real bargains — when housebuilders were desperate for cash and gave discounts of up to 40 per cent on finished homes — is over.

The reason is that developers are starting to benefit from the mess they found themselves in. Meanwhile, would-be buyers are confronted by a market starved of new homes because housebuilders have been unable, or unwilling, to finance developments or to make their costs stack up against current prices. In the South East, one of the most resilient regions, the number of homes started last year was down 36 per cent on 2007 and at the lowest level since the Second World War. “Homes being completed now would have to have been started in the depths of recession. Not enough people were brave enough, or stupid enough, to do it,” says Yolande Barnes, head of residential research at Savills, the estate agent.

In Cambridge, David Bentley, who heads the new homes office of Bidwells, another estate agent, says that finished stock was being sold at a discount last year but there is very little left. “In areas where there’s a good track record of capital growth, homebuyers will need to get used to buying off-plan again,” he says.

The housebuilder Taylor Wimpey says that most of the new homes it will complete this year have been sold and it is considering starting up to 40 developments this year to sell off-plan. “We will focus on more southern areas and there will be an increase in the number of family homes,” says Kevin Belsham, the sales director.

The picture is by no means the same everywhere. In the east and west Midlands, Chris Watts, of the estate agent Paul Carr, says that a shift from selling finished homes to selling off-plan is still some way off. “Some developers have almost been forced into discounting to move product and that is still happening,” he says.

However, developers are showing signs of renewed confidence. The number of new homes started in the UK in the three months to June was 21,600, up from 16,300 in the first three months of the year, according to research by Knight Frank and the National House-Building Council. The New Homes Marketing Board (NHMB), part of the Home Builders Federation lobby group, senses enough optimism among its members to try to repeat a promotional drive last held in 2006 to hammer home the benefits of buying new.

Fronting the New Homes Week campaign is David Pretty, the former Barratt boss, who says that there are “some fantastic deals out there”. The campaign offers useful advice to would-be buyers: for example, if no deal is openly advertised, ask the sales team if the housebuilder is open to offers on the asking price.

But, given the shortage of new homes in many areas, how much discount should you ask for? Well- researched buyers should know how desperate the developer is to make a sale. “You need to do your homework,” says Jonathan Vandermolen, a former estate agent who helps banks to deal with the loans they make to residential developers.

If a flat is not discounted by at least 20 to 25 per cent of the price it would have sold for at the top of the market, you should not be buying it, he says. “Depending on location, new-build houses could be down by only 10 per cent. If you are buying for your own use or as a long-term investment, spend on houses rather than flats.”

Ultimately, the most important number will be the value that your mortgage lender will let you borrow against. This will be based primarily on comparable sales. A vast amount of useful data is available online, including on the Land Registry website.

Yolande Barnes recommends paying close attention to the prices that second-hand homes are selling for in the area. “At the height of the boom, there was a huge premium attached to prices for new-builds. There is no reason for that now,” she says.

But Rupert Dawes, head of new sales at Knight Frank in London, says that premiums are creeping back for new homes in desirable locations in the capital. “If there are ten people looking at two or three flats, it may be worth paying a premium,” he says.

Cash discounts are not the only incentive to look for: ask whether the developer will provide help with the deposit, legal costs, stamp duty, moving costs and part-exchange deals if you own a property. The leading housebuilders’ websites show a confusing proliferation of these deals, but always accompanied by those magic words “on selected sites only”.

New homes can also offer long-term savings. They can be up to 60 per cent more energy efficient than older homes thanks to better insulation, according to the NHMB.

But if you can’t find your perfect new home this autumn, don’t give up. “Buyers are becoming much more discerning in terms of the amount of space and the level of finish they expect,” says Barnes. “And that is something more developers are now having to respond to.”

Times recommends

• Second homes: credit crunch casualty or money-spinner?
• How I built my own sliding house
• Top 10 incentives for house buyers