Generally speaking, the best value I have found for panels are used panels pulled from solar farms when the companies get tax breaks. It seems like most of these panels come from Arizona thru Santan Solar, and in most major cities there is someone selling panels they got from Santan on Craigslist. They get 235-280 watt panels for $50 and sell them to you for $100 and they typically have 5 years on them.
My entire cabin uses these panels, it’s pretty hard to beat unless you are buying enough to go direct to Santan and can make the freight worthwhile.