Where could i buy a microscope that w ill connect to my computer would consider second hand?

Most 'Pound Shops' sell them, HyperValue, PC World. They are cheap enough.Where could i buy a microscope that w ill connect to my computer would consider second hand?
Digital blue sell theseWhere could i buy a microscope that w ill connect to my computer would consider second hand?
try ebay.co.uk
ebay.co.uk