Best websites to help you save big bucks on holiday shopping

The National Retail Federation estimates almost half of all holiday shopping will be done online this year.

But with prices constantly changing, you may want to check out some websites that will make sure you get the best deal.

Yolanda Machado said she buys most of her holiday gifts online and has her hands full this year with her family wish list as her family wants a variety of things ranging from a laptop to a Playstation 4.

Fortunately, there are a variety of apps that can help find great deals on items like these.

Consumer savings expert Andrea Woroch said she uses a price comparison tools like ShopGenius or InvisbleHand.

They run in the background while you're shopping around online. If what you're about to buy is cheaper at another retailer, they alert you before you purchase.

Woroch said this website does all the work for you, so you don't have to look at other websites. The laptop for Machado's daughter was first found on Amazon for $330, but InvisbleHand found it on Best Buy for $279.

If electronics are on your list, then check out Greentoe where you can name your own price. They negotiate with retailers for free.

For example, Beats Headphones for Machado's husband once cost $99, but she got them for $72 and that included shipping and tax.

The savings don't have to stop once you've made your purchase because websites like Slice and Paribus work to get you money back on stuff you have already bought.

When you give Paribus access to your email, they can scan all your sales receipts and if they find a better price elsewhere they'll file a claim with the retailer for a price match.

Your account is automatically refunded and Paribus takes 25 percent of whatever savings they find you.

The National Retail Federation estimates almost half of all holiday shopping will be done online this year,