Dont sell to camera stores... It would be like trading in your car to a dealership vs reselling on ebay/craigslist/newspaper. Stores and dealerships have to buy your gear low enough because they cant sell them for new prices, so they got to make it worth their investment, sort of speak, and a $5-10 profit margin isn't worth their time. I've had camera stores tell me to sell my gear on ebay or craigslist because they admitted they couldn't offer near the amount they are worth. Secondly, your canon lenses typically hold their value a tad bit better than quantaray or even tamron, sigma, tokina, etc. If your gear is near mint condition, i would recommend posting a free craigslist ad for a tad below the new import prices you see on adorama/bh photovideo and see what bites you get.