Online shoppers plan to spend more on holiday gifts this year, with 66 percent indicating they will spend over $500, according to a new report from PriceGrabber. Last year, more than half (59%) of shoppers spent $500 or more on gifts. This year, the average amount that holiday shoppers plan to spend on gifts is $845. According to survey data, the average 2010 holiday shopper will make 57 percent of their holiday purchases online, 40 percent in brick-and-mortar stores and 3 percent from a mobile phone.