While Labor Day promotions have already been going on all week (despite the holiday itself still being another three days away), some early deals have been fairly attractive. A noteworthy one is eBay’s 20 percent off sale on refurbished items, which is running through September 4th when you use code LABORDAYTWENTY at checkout. You can use this deal twice to save up to $500, and while plenty of crap is on offer, there are some genuinely good refurb deals to be had, many of which include a…