What is there to make you sick? Some sellers prefer to either sell for a high price or keep the item if the price is not meet, others prefer to sell at low prices and get rid of their items. Sellers own choice, if you want to sell your Chaos Engine II for 60 quid, do so, but don´t expect it to be sold. The same goes for the Agony game, unless a seller is missing it in his/hers collection.
