I would just like to add that I, yes ME, have taken my very own Year Two class to the local Tesco store for an educational trip linked to our topic of food. It was very educational. The children no only learnt about where in the world our food comes from (fruit and veg aisle) but they also learnt that there are many different types of fish (not just cod or haddock that is fried!) and how food is stored (we went into their large walk-in freezer and fridge), warehouse and also about jobs and the many people and roles it takes in a supermarket. The children found it entertaining with an educational spin on it and yes, they also made their own bread rolls which they took home.
Just because a store website doesn't have details about educational visits, doesn't mean it doesn't happen! The store manager could have arranged it as a special 'one-off'.
I must admit as a teacher who has taught the topic of toys, it isn't the first place I would visit but sometimes teachers need a stimulus to get the children engaged. There are 'better ways' to do it (museum - but not all children have access to a toy museum) and usually asking children to bring in a favourite toy is usualy all that is needed.
OP - obviously you like the school, other-than their wild idea of going to a toy store, but instead of making a decision based on facts you do not have, as you said yourself, why don't you arrange a meeting with the class teacher/head teacher and ask for a full itinerary of their visit and what the learning objectives are. I am not saying that you will, but you might be pleasantly surprised.
But I wouldn't allow ANY child to take money. That IS commercialism. Educational trips should not involved children spending money to buy toys.