Although Cyber Monday is over, consumers are still heading online to finish their holiday shipping. Many of these shoppers are going to be looking for sites that offer free shipping, but is that free shipping really free? Sometimes it isn't. A simple free shipping offer can induce consumers to spend more than they had planned simply so they can reach the free shipping threshold. This was actually one of my five budget-busting Cyber Monday mistakes, but this is one mistake that online retailers are counting on to help boost sales this holiday season.