Why you’re paying sales tax on that Cyber Monday deal, but others aren’t

It's Cyber Monday, that time of year when millions of us will rush to online retailers like Amazon in hopes of scoring a great post-Thanksgiving deal. But if you live in one of a handful of states, your "savings" will be affected by the collection of online sales taxes -- an issue that has grown increasingly controversial as e-commerce has become a huge part of holiday sales. This weekend alone, 103 million people shopped online, spending $4.4 billion between Thanksgiving Day and Black Friday, according to the National Retail Federation. What you'll pay in sales taxes often depends on a number of factors, including where you live, where your seller is based and -- not surprisingly -- the outcome of a years-long legislative slog in Congress. As you complete your holiday shopping list, here's what you need to get up to speed.