We're entering the final frenzied push to Christmas Day, the holiday is just one week away.

The National Retail Federation says many shoppers are trying to wrap up their search for gifts online, and many of them were doing on December 18th.

That's because December 18th has been dubbed "Free Shipping Day" with nearly 900 retailers participating on the official website.

There's no charge to ship on the 18th and there's no minimum purchase required. A link to the official "Free Shipping Day" website is posted at the end of this article, but first there's more information you should know. 

Shipping Deadlines Coming 

For many retailers, deadlines are fast-approaching if you want your deliveries to arrive by Christmas Day.

example, Walmart says Thursday is the last day you can order on its website, with standard shipping to get your gifts by the 25th.

If you order Friday, you'll have to rely on selected expedited two-day shipping, which costs at extra $2.97. Walmart also says same-day, in-store pickup is available through Christmas Eve.

Other retailers have similar deadlines.

According to NBCNews.com, Toys 'R Us has a deadline of 3 p.m. on December 19th. Zappos.com has the latest, promising standard shipping for orders that are made before 7 p.m. December 22nd. 

Here's a link to a chart with the deadlines for more than two dozen retailers: http://www.nbcnews.com/business/clock-ticking-christmas-gift-shipping-2D11764483 

Here's a link to the Free Shipping Day Website: http://www.freeshippingday.com/