Also known as American Sweetheart, depression glass is something to be happy about. Some patterns and colors are more desirable than others, so if you have a rare color or pattern it could be very valuable; the American Sweetheart pattern is especially valuable in ruby red or cobalt blue, says Hirsch. You can expect to fetch around $30 to $75 dollars a piece. Full sets, like the American Sweetheart eight-piece tea set, recently sold on eBay for $405, says Reyne.