This is a 3mm red LED, without flat side or other external polarity indication. But seeing through the body you can make out the "cup", which connects to the negative lead (= flat side on a LED that has one)
This product is sold by 10, the price is for 10 items.
This is a surplus product. It was obtained from a surplus store, from an inventory or from any other secondary source. You can expect this product to be in good working condition, but it can show signs of being handled, shipped, repackaged etc. The supply of a surplus article can suddenly run out, or the price can change. Get it while it is available.