I will be visiting Madrid this summer (July), and would like to know if there's any store where I can buy official Spanish National football team products? Is there an Adidas store that sells them?
A quick Google search turned up the official online store. The address given is C/ Ramón y Cajal, district Las Rozas. Google Maps shows a putative location for the shop, but Street View shows that there's nothing there. However, just to the north is the Museo de la Selección Española de Fútbol which probably has a gift shop.
If you're looking for Real Madrid, the first hit on Google points me to this store location.