I go here once a month to buy a 10-kg sack of vegan dog food. Despite being a small store (just one room), the price of the dog food and of many other items are lower than in other health-food or organic shops such as Veritas. Unfortunately, organic, vegan, and health foods are very expensive in Spain as the associated lifestyles have a lesser following than in, say, the UK or Northern Europe, and demand is quite small. This also means many of the products in this shop are imported (as they are in other similar shops in Barcelona), and therefore more expensive than those at a regular supermarket.
The owner of Veganoteca doesnt just import foreign goods, though - he is dedicated to spreading the cause locally. For example, he reached out to a local (conventional) baking company and showed them how to use an apple glaze instead of gelatin to make delicious & totally conventional-looking croissants, which he then sold in his store (to my great joy). He also sells merchandise for local animal rights organizations, and activists use the shop's back room for some of their activities.
Besides being super grateful for all that the owner does for veganism in Barcelona, the products are well-priced, given the situation, and extremely delicious. Worth a visit each and every time you're in the neighborhood!
Cons: there is only one of it, not open 24 hours a day, not next to my house