Is Amazon always the cheapest place to shop for the holidays? When is the best time to buy a gift like a Barbie doll or J. Crew sweater?
The Wall Street Journal set out to study those questions by tracking daily online prices of items across several retailers since Oct. 1.
With help from research firm Thinknum, we measured prices each day for three categories: toys, electronics and sweaters. Scroll down for a list of the specific items we tracked, which we kept hidden until now.
Here are seven things we learned:
1. Some of the steepest discounts on the toys we tracked were available in early November, before Black Friday.
2. Target had some of the cheapest prices on toys early in the season, and then Wal-Mart began cutting toy prices closer to Black Friday.
3. Despite its September bankruptcy filing, Toys 'R' Us offered the least competitive prices on toys.
4.The biggest markdowns on electronics weren't available until the week of Black Friday, and then prices went quickly back up.
5. Amazon had the lowest prices on electronics in the weeks before the busy shopping weekend.
6. Best Buy and Amazon had the lowest prices on electronics in December.
7. December was the best month to buy discounted sweaters at apparel chains. J. Crew had the deepest discounts for much of the season.
Here are the items we tracked:
-- Nerf Rival Nemesis MXVII-10K, blue -- Barbie Rainbow Lights Mermaid doll -- Disney Junior Doc McStuffins all-in-one nursery -- Lego Star Wars The Last Jedi BB-8 -- Nintendo Switch console with gray Joy-Con -- Fisher-Price Laugh & Learn First Words Smart Puppy -- FIFA 18 Ronaldo Edition for Xbox One -- Disney Pixar Cars 3 Ultimate Florida Speedway track set -- FurReal Roarin' Tyler, the Playful Tiger -- Paw Patrol Sea Patroller
-- Nikon DSLR D3400 camera -- Samsung Electronics 55-inch 4K Ultra HD Smart LED TV (2017 model) -- Sonos Playbar -- Xbox One 1TB console -- HP Officejet 3830 all-in-one printer -- Fitbit Alta fitness tracker, large -- Nest Learning Thermostat, third generation, stainless steel -- Apple iPod Touch (32GB) -- HP 14" Chromebook -- Call of Duty: WWII