Some Retailers Open More Than 100 Hours Straight Even with the travel, this is a big weekend for marathon shopping, for a lot of american families, macy's and k-mart will keep stores open for more than 100 hours in a row, from now until christmas. And also this year, there may be a new chance to negotiate the price way down, abc's paula faris has that. Reporter: Stores are at an all out war for your business with five days until christmas, some retailers open around the clock. Catering to late game shoppers you like to wait until the last minute? I don't like to. It just happens that way. Reporter: These next few days are four of the busiest in the holiday season, with an estimated 51 billion to be spent. And our retail expert mark ellwood says, you're the one who benefits. This is the most desperate I've ever seen retailers. Reporter: Tip number one, you waited this long, hold out. ON DECEMBER 24th, THERE IS Going to be a panic among retailers, to off load whatever they can, before the scrum of after christmas sales begins. Reporter: Retailers continue to price match, just make sure you ask for it. Tip number two, to find the best online deals, install price blink to your browser, it scours the internet for the best prices. That's how we found christmas favorites like wonder loom bracelet kits for 12.88 nearly $10 cheaper than a competitor and a canon for $129, 50 bucks below list price. Don't be afraid to negotiate. Are there any coupons today? 15% off today. Great. Is there anything else it can be combined with? Reporter: Our expert shows how it's done going undercover. So it's $25 but I'm paying -- $5.44. Reporter: Goodbye full price, hello holiday deals. Paula faris, abc news, new york. And another retail note