In a shop mainly targeted towards tourists visiting Manneken Pis, you know everything will be more expensive, especially when it looks more appealing and fancy than many others in the area and appears to sell premium products.
While the chocolate and candy range indeed includes a few (overpriced) top products, the beers are mostly the 'normal' wide variety of Belgian brands that can be bought 50% to 60% cheaper in supermarkets like Carrefour, Delhaize, Match, etc.(e.g. reference price for a 33cl Westmalle or Chimay bottle is around 1.40 EUR in a supermarket).
Finally, be careful to check the price when you make your own self service mix of candy and chocolates, and weigh regularly to avoid surprises. read more