Come Monday, the post office is going to be packed, because that is the last day to get your gifts shipped out using the least expensive options.

"It is going to Seattle, Washington, and his birthday is close to Christmas so it is a joint Birthday-Christmas gift," said Elizabeth Fulghum.

Fulghum is shipping out the last of her Christmas gifts before Monday's deadline. She's not only beating the rush the deadline brings but also saving money.

"I always get it done early because I do not want to wait to the last minute and then have to pay extra for shipping," Fulghum said.

While you can still send cards and letters and gifts after December 17, getting those packages to their final destination on time will cost you more money after that day.

"I tell the people, come early, like before Tuesday of next week and they are still OK," said Ameesh Patel with the West U Pack & Ship.

Patel says if you want things to arrive in time for the holidays and at the best price, act quickly. He adds Monday is going to be very busy in the shipping industry.

"The biggest day is Monday. Monday is the last day for the ground shipping. Some of the things will not get there after Tuesday, like Washington, D.C., California, Seattle," Patel said.

Mailing before Tuesday can save you big bucks.

If you ship out a three-pound box to California before the end of Monday, it will cost you $15. A day later, that same package will cost you $35 to $40.

If you have yet to buy a gift, December 17 is even more important. Dozens of websites are offering free shipping, if you buy on Monday.