Teenage girl using laptop computer at Christmas

A new wave of websites have been created offering big discounts, but they're only available for a limited time.

Members-only websites offering "exclusive" flash sales and heavily discounted items are a great way to buy designer goods at a discounted price.

They are able to offer significant discounts because they buy surplus stock from a retailer after it's finished selling it. The brands on offer vary, but they are generally high-end and delivery times are longer than with traditional retailers.

Daily offers are emailed out to members and most sales are only available for a limited amount of time.

The top secret bargain websites

Achica

The members-only luxury lifestyle store which anyone can join, Achica offers discounts on high-end luxury goods. Each time a sale is announced it's only available for a short period of time - either 24, 48 or 72 hours - and these sales only take place during the week.

A lot of the items on sale are luxury home and garden pieces. For example, right now you can buy a Wobabi goat skin chair for £229, down from £355, a Dalian Chinese vase for £8.99, down from £40, or a Dora Designs Scottie doorstep for £15.50, down from £25.99.

From 6.30am every morning the site is open for shopping. There is a limited number of each product available, so it's worth looking early if there's something you want to buy. The site is free to join and when you become a member you'll be emailed with details of each sale.

There are gift vouchers available and there's a blog on the site with lots of inspiration for styling your home. You'll also get a voucher for £10 for every friend you recommend who then buys something.

Brand Alley

Described as a "non-stop designer sale" Brand Alley offers discounts on clothes, homeware, beauty and theatre tickets.

It says it'll knock up to 70% off designer brands and deals are only available to registered members.

Sales last between four and seven days. Offers at the moment include 46% off Kurt Geiger men's brown Chelsea boots, 39% off the cost of a Ted Baker dress and 54% off the cost of a set of six Irvintgon towels, down from £105 to £49.

Once again, to keep costs down, delivery times are longer than normal and items can take between seven and 28 days to arrive. Each time you invite a friend you'll both get £10 when they make their first purchase. Members will be emailed each morning with details of that day's listings.

Hush Hush

This is a website from the founders of MyVoucherCodes.co.uk and offers savings on a range of goods including homeware, fashion, beauty, pets and food.

Delivery periods tend to be between 14 and 21 days, so it's not ideal if you need something in a hurry. Each week there are between 15 and 25 secret sales and these last for around four days.

Most of the items on the site are reasonably priced and current deals include a Ben 10 Hero duvet set for £5, down from £25, a tall bamboo bathroom unit for £10, down from £49, and a blue leather satchel bag for £59, down from £105.

When you sign up you'll be given a £5 credit, which can be redeemed on purchases of more than £30. And if you invite 10 friends you'll be given £20 free credit.

Secret Escapes

If you're planning on getting away for some winter sun, or maybe a trip for next year, Secret Escapes is another members-only website offering discounts of up to 70% off the normal price for travel and accommodation.

It's not exactly a bargain site, as the holidays are "luxurious" and "hand-picked" and have to be either four- or five-starred to be included. However, if you were going to book one of these trips anyway, the discount is pretty impressive and it's worth checking out.

There are flash sales on offer to locations around the world and members are emailed beforehand with details. The sale is then open for around 10 days. It guarantees to give you the cheapest prices on the deals on offer – but all prices are kept secret until you sign up.

There's a membership incentive of £5 for every friend that joins and you'll get a £25 credit for each purchase the friend makes. It's also a member of ABTA so you're covered should anything go wrong on the trip.

Earn cashback on your Christmas spending

Secret Sales

This is another secret website, where deals are only available to members. Founded in 2007, the items on offer aren't cheap but they are a lot cheaper than the prices on the high street.

For example, you can pick up a pair of PUMA by Alexander McQueen shoes for £59, down from £150, a Tresspass coat for £59, down from £160 or a single duvet set from the V&A for £30, down from £60.

Daily sales start at 7am and last up to 10 days, with current and upcoming sales listed on the home page.

Orders are only processed after the sale ends so will take longer than normal, but you should be given an estimated date of delivery.

Outlet shops

Outlet shopping, both online and in branch, is a good way to save money if you don't mind buying items which are out of season. Marks & Spencer, for example, has an online outlet website listing all of last season's products at greatly reduced prices.

Websites such as Cocosa and The Outnet work in a similar way and sell off high-end designer goods at discounted prices.