Hiya,

Not been to Magaluf but in Alcudia I would say that those prices are about right, nappies etc are also expensive I know that it's not ideal but I really would try to take as much over with you. I never had luggage allowance for my two and managed to take everything but the kitchen sink

As for Spanish brands of items they don't really have them, the items are just the same as ours with maybe slightly different names(Pampers were Dodots) and cost wise they're the same.

The big supermarkets sell all types of baby food, the make is HERO, they tend to put pictures on the bottles so that you are able to see what type of food it is. They also put the age on there, i.e) 4+ is four months onwards
it is normally about 1.50€ a jar.
The chemists also sell a lot, however they are more expensive, I would suggest that you bring a few jars to be going on with and then go to the local supermarket and stock up.
Eroski or Mercadona are the normal ones to shop at and also are the cheapest.

To be honest it will not be a problem to buy it just don't go to the local shops as they charge about twice as much.