If a Seller is selling at a higher price, he will not be able to sell it at that price for a long time because buyers will not buy from him and thus he will be forced to reduce his price. So, there is nothing to worry about high price. You just have to buy from a Seller who is selling the same item at the cheapest. If you block a seller, only you will not be able to buy from him while others can. So, what's the benefit? Just ignore the rest and be happy with your choice of sellers.